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Alistair Riddell
Experienced User
Username: ariddell

Post Number: 33
Registered: 1-2013
Posted on Wednesday, 29 October, 2014 - 09:36:   Edit PostDelete PostView Post/Check IP

Hi All,

The climate control system in 25955 has been playing up for a while, and has now ceased to function completely. For quite a while it would not power up when the car is running until a random period of time after starting the car, usually 15-20mins or so, it would then operate as normal with all actuators and controls working fine. Stop the car and restart and it would be hit and miss if the climate control would come back to life again without another delay.

Now I'm getting absolutely nothing, system does not come to life at all. I've replaced the relays for the system under the bonnet and the one on the right hand side in the boot. I've also checked and I'm getting 12v at the ECU with the engine running.

I notice the climate control ECU has a red LED on it, this never lights up at all on mine, should this be illuminated if the ECU is operating?

Any assistance appreciated, my suspicions are my climate control ECU has failed but it'd obviously be quite an expensive gamble to buy another one to swap out.

Thanks,

Al
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Bob uk
Unregistered guest
Posted From: 94.197.122.71
Posted on Wednesday, 29 October, 2014 - 11:24:   Edit PostDelete PostView Post/Check IP

That sounds like a dry joint in the ecu.
get the ecu checked.

I had a motorbike ignition system lose a cylinder at random and it was a simple dry joint on the pcb. The fault would cure it's self for days then suddenly 3 cylinders. It was so annoying because it would start up and suddenly run on 4 and so on.

The pcbs are wave soldered by a machine and then tested on a bed of nails, if it works it gets fitted to a car. If not it's scrapped. The test doesn't detect dry joints which play up 20 years later.

A garage would likely check the ecu by substitution.

Obviously you have enough knowledge to check that the ecu has a feed. If the ecu comes apart check the soldered side for dry joints by pushing a plastic probe against the soldered blobs while the ecu is in circuit.

I have never seen an eco with a led indicator. Good idea if it's meant to flash a fault code. So the led reason is worth pursuing because my jeeps engine management light flashes a code if the ignition is turned on off on off on. Which totally confused me and made me think it was the ignition when it was no5 injector pulse missing because the wire had fallen out of the ecu plug.

(Message approved by david_gore)
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1294
Registered: 6-2006
Posted on Wednesday, 29 October, 2014 - 20:03:   Edit PostDelete PostView Post/Check IP

Hi Alistair,

Are you not getting anything at all (no servos whirring) or just no fans?

If you put on defrost or use the facia switch, does it do anything?

The LED is used to set up the servos. Details are on the manual disc. Along with test procedures.

Not sure if there's anybody in Aus with a test rig but we can test them / repair them here in the UK.

Is there somebody nearby with a similar age car you can try a substitution on?

Fairly reliable boards and great (if not a little confusing for some) while they are working . . .

Regards, Paul.
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Alistair Riddell
Experienced User
Username: ariddell

Post Number: 34
Registered: 1-2013
Posted on Wednesday, 29 October, 2014 - 21:45:   Edit PostDelete PostView Post/Check IP

Thanks guys, I get absolutely nothing at all, no fans, no actuators, totally lifeless in all switch positions.

Previously when it was working intermittently I would occasionally hear what sounded like the actuators working weakly at times until the system kicked back to life and everything worked full strength.

Alas I don't have access to another ECU I could easily swap out to test, a local wrecker has one but is asking over $1000 for the board with no guarantee of success so reluctant to go that route until absolutely sure my ECU is at fault and unrepairable.

Rgds,

Al
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1295
Registered: 6-2006
Posted on Thursday, 30 October, 2014 - 02:19:   Edit PostDelete PostView Post/Check IP

$1000 ouch!!

Much cheaper and safer to have it tested and repaired if necessary.

Cheers, Paul.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 3114
Registered: 4-2003
Posted on Thursday, 30 October, 2014 - 13:25:   Edit PostDelete PostView Post/Check IP


quote:

I notice the climate control ECU has a red LED on it, this never lights up at all on mine, should this be illuminated if the ECU is operating?



The LED is there for calibration purposes. Best inform yourself. It is explained in detail in the Technical Library. The LED will only operate under test mode where a link plug is required to be applied onto the ECU motherboard.

If you select demist, does the fan blow ?

You may simply have depleted refrigerant in the compressor circuit. That stops most functions but not the demisting.

Before even dreaming of touching the ECU, there are yet more tests which I may describe later. There is no reason to suspect the ECU just yet.

RT.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1296
Registered: 6-2006
Posted on Thursday, 30 October, 2014 - 20:06:   Edit PostDelete PostView Post/Check IP

Richard , over here depleted gas only stops the air being refrigerated but the fans and actuators will still attempt to give what is requested.

Alistair, run through the connections to make sure all feeds, earths, and sensors are present.

If you look at the wiring diagram / system diagrams there are few things that will stop everything working and others that just stop the fans working.

Boost starting on a completely flat battery can spike the boards , but as I mentioned, they are pretty robust.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 3115
Registered: 4-2003
Posted on Thursday, 30 October, 2014 - 23:31:   Edit PostDelete PostView Post/Check IP

Sure, Paul,

My main question is that when DEMIST (knob fully clockwise) is selected, do the blower fans operate ?

If so, on 20k+ cars (1987+) it could be the fan speed module burned out or just a relay issue.

The fan speed module (resistor block), the main cause of all this, is often dud, expensive at over $2,500 new until recently and now NLA. I make new ones from scratch with a new heatsink but using semiconductors instead of resistors to drop then fan speed, all up for less than $30 for the raw parts only, but I have no plugs left so recycle that trivial bit. Having applied several now, the first in 2001 and the most recent last week, I can say that the replacements are functionally identical and will last far longer. Add time costs to assemble it and to Remove/Refit, it would set you back only a few hundred at the going rate of $250/hour.

RT.
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Ernest Carty
Experienced User
Username: edcarty

Post Number: 46
Registered: 12-2012
Posted on Thursday, 30 October, 2014 - 23:35:   Edit PostDelete PostView Post/Check IP

I would check the connections to to Temperature switches on the Engine as if these sensors are faulty then the Air Con cannot recognize certain requirements,details of these switches and sensors can be found in the manual,also check the main Earth terminal under the Air con board situated on the transmission tunnel as this is prone to corrosion.Hope this helps
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Bob uk
Unregistered guest
Posted From: 94.197.122.90
Posted on Thursday, 30 October, 2014 - 06:36:   Edit PostDelete PostView Post/Check IP

600!! the vendor is going to be owning that ecu for a long time.

I paid 50 to have the motorbike pcb fault checked and repaired. The repairer said that dry joints are common.

(Message approved by david_gore)
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Bob uk
Unregistered guest
Posted From: 94.197.122.80
Posted on Friday, 31 October, 2014 - 06:53:   Edit PostDelete PostView Post/Check IP

Re reading this thread has jogged my memory.
many years ago I had a Ferrari 308. Which had hit and miss ac. This car had a low pressure switch. We temporarily bridge the switch for 2 secs and the ac came to life. The pressure sometimes was just enough to fire the ac up and other times it wasn't. When we checked the low pressure side the pressure was on the cusp of minimum. So we put some R12 in and the system worked fine. Then we serviced the ac properly.

So before doing anything else check the low pressure pressure.

The 308 was 25 psi which is minimum we charged it to 45 psi If my memory is correct.

The owner said that the ac worked better than he remembered, meaning the ac had been running low pressure all the time he has owned the car.

The system on the SZ is far more complex. So one must not bridge sensors. However the fridge bit is the same. How much of the system is interlocked with the fridge bit I don't know.

(Message approved by david_gore)
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 3116
Registered: 4-2003
Posted on Friday, 31 October, 2014 - 21:39:   Edit PostDelete PostView Post/Check IP

The three second test first of all as this override function tells quite a lot:

If you select demist, does the fan blow air to the screen ?
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Alistair Riddell
Experienced User
Username: ariddell

Post Number: 35
Registered: 1-2013
Posted on Saturday, 01 November, 2014 - 09:23:   Edit PostDelete PostView Post/Check IP

I have now run a test with the engine running and the switch set to the defrost position and can confirm I get absolutely nothing in the way of activity from the system in this mode too.

No fans, can't hear any attempt at actuation, nothing.

Rgds,

Al
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Nigel Johnson
Prolific User
Username: nigel_johnson

Post Number: 134
Registered: 12-2008
Posted on Monday, 03 November, 2014 - 20:21:   Edit PostDelete PostView Post/Check IP

ACH 01253 has the same symptoms, no fans nothing. Just started today. The ACU fuse has blown, I replaced it and the new one sparked and blew. The engine was running at the time.
Regards, Nigel.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1301
Registered: 6-2006
Posted on Monday, 03 November, 2014 - 21:04:   Edit PostDelete PostView Post/Check IP

Nigel,

Yours is a different system. Was the fuse in the engine bay? Have a look at the relay nearest the fuse.

The terminals overheat and cause problems.

How quickly does it blow? Turn off the engine and turn on the heating controls. Renew the fuse then start the engine. Note when it blows.

Cheers, Paul.
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Nigel Johnson
Prolific User
Username: nigel_johnson

Post Number: 135
Registered: 12-2008
Posted on Monday, 03 November, 2014 - 22:40:   Edit PostDelete PostView Post/Check IP

Thanks Paul, I put a new fuse in and started her. The fuse went as soon as I turned the aircon switch.
Regards, Nigel.
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Nigel Johnson
Prolific User
Username: nigel_johnson

Post Number: 136
Registered: 12-2008
Posted on Monday, 03 November, 2014 - 23:07:   Edit PostDelete PostView Post/Check IP

Sorry Paul I should have added the fuse is in the fuse box. I'll check the relays later. The reservoir leaks slightly and could have wet the relay terminals.
Regards, Nigel.
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Nigel Johnson
Prolific User
Username: nigel_johnson

Post Number: 137
Registered: 12-2008
Posted on Tuesday, 04 November, 2014 - 04:41:   Edit PostDelete PostView Post/Check IP

Oh dear. After further examination I found one of the two main wires that connects to the compresser has a bare patch and was shorting on the inlet stove pipe.
All sorted now, but I will now have to buy some 10amp bulgin fuses.
Very sorry to hijack this thread, but it seemed very serious this morning
I'll ring you tomorrow Paul.
Regards, Nigel.
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Alistair Riddell
Experienced User
Username: ariddell

Post Number: 36
Registered: 1-2013
Posted on Tuesday, 02 December, 2014 - 11:55:   Edit PostDelete PostView Post/Check IP

Well, I have done a fair bit of further investigation on my car but still no further forward with a resolution alas.

By bridging the fan control relay I can cause the fans to run, and bridging each fan speed relay causes the speed to change accordingly.

I have checked the control switch and am able to see the appropriate pins at the multiplug forming connectivity as the switch is moved to the various positions. Tested at the multiplug just behind the switch panel. I have also tried bridging the aircon coolant sensor.

I have also been able to swap in another climate control ECU to see if this resolves the issue, however it didn't and I'm no further forward.

Still no actuation of flaps or any activity from the fans however, my climate control system is entirely dead.

In addition to this I have gone round and stripped and cleaned the under bonnet and A post earth points indicated in the climate control wiring manual, also to no avail, although I didn't expect this to be the cause since multiple items are earthed here so suspect more than just climate system issues would have been being experienced had this been the cause.

Getting to the point of severe frustration as it has basically rendered the car unusable with the temperature climbing as summer gets going.

Any ideas on other tests I can run to try to identify where the issue preventing my system activating resides?

Rgds,

Al
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Alistair Riddell
Experienced User
Username: ariddell

Post Number: 37
Registered: 1-2013
Posted on Wednesday, 03 December, 2014 - 09:32:   Edit PostDelete PostView Post/Check IP

An interesting development, I found that the wiring on my A1 fuse is the opposite way round from how the manual stipulates. So in the process of other investigations I retried feeding a known good 12v feed to the correct wire to send power to the climate system (in my case I used the interior lighting circuit to feed it), low and behold the sound of actuators whirring from behind the dash!

On measuring the voltage with the engine running I am seeing 14v on the interior light feed, but only 11.6v on the feed coming to the climate system on fuse A1. Further tracing of this has shown it takes the feed for this supply from the "Warm up Regulator Inhibitor" relay under the steering wheel.

Swapped this relay out with a good one, and put the fuse board connections back how they should be and I now have actuators at least back to life!

Progress, finally! I had confirmed I had voltage at the ECU pin previously, but it had not flagged to me that this was lower than it perhaps should have been.

Now to put things back together and see if I can see why the fans still didn't seem to be kicking in.

Given the actuators have been moved around in my testing of various parts, do I now need to re-initialise the ECU?

If so, how do you go about loosening the rods as indicated in the manual for the process. I had a feel around in the area the manual suggests but it appears rather inaccessible.

Rgds,

Al
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Bob UK
Unregistered guest
Posted From: 94.197.122.78
Posted on Wednesday, 03 December, 2014 - 11:51:   Edit PostDelete PostView Post/Check IP

Check the alternator out put using a digital multimeter it must be as the book says. Also check the battery careful.

I say this because ecu can shut down if voltage is low.

I wouldn't mess with the rods because adjustments are bound to be needed after assuming that they were correct which unless the elves have messed with them. I think the flaps will sort themselves out when the system comes back to life.

The voltages you are recording are they the same wheather the earth on the ecu is used or the body of the car.

Also check the fat Brown wires which are live, around the starter motor, alternator and the main connection for the whole car.

This system what with actuators and fans uses a bit of power which has to come from the fat Brown wires.

Also check the air con charge level.

If the level is low then the aircon can go into overdrive trying to keep up and pop something.

(Message approved by david_gore)
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Andrew Radford
Yet to post message
Username: thequalitybuilder

Post Number: 1
Registered: 4-2015
Posted on Saturday, 03 October, 2015 - 22:36:   Edit PostDelete PostView Post/Check IP

Hi All
Ive been using this forum for info for almost a year for my 1998 Brooklands Mulliner so would like to thank you all for the help it has provided, I have a heater problem, my car had a leak on the ac condenser when I bought it so no AC and no heat except on defrost. Ive fitted a new condenser, now have cooling ok and heat on defrost, but still no heat, I used the test rig and 40 deg sensor light on test never went out, so ive fitted a new 40deg sensor (what a job!!) anyway still no heat except on defrost, (the interior fans do run when on hot but blow cold air) Im guessing could be faulty new sensor?(guess I could test the old one) heater tap, or also i've seen something about initializing the board which i've had checked and upgraded (does this need doing), any ideas, I don't have access to the test rig at the moment and the sensor is buried under the charge cooler. Any ideas what to look at first?
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 3234
Registered: 4-2003
Posted on Saturday, 03 October, 2015 - 23:26:   Edit PostDelete PostView Post/Check IP

Question. When on Defrost is the air really hot - amd I mean stinking hot ? If so that eliminates the heater tap as the culprit. If cool or only warm watch this space.

RT.
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 2
Registered: 4-2015
Posted on Sunday, 04 October, 2015 - 02:54:   Edit PostDelete PostView Post/Check IP

Ive now done a bit more investigation. I always get heat via the defrost, does this mean that the water system must be full and not airlocked? (It would help to eliminate some possibilities) Also Would it tell me anything about the function of the heater tap?
Heat does always come from the vents momentarily when I change from defrost to auto however this often goes cold but not always. I do seem to get bits of heat sometimes if i jerk the car whilst driving! Strange to me but may be one of you guys might be able to help.
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 3
Registered: 4-2015
Posted on Sunday, 04 October, 2015 - 03:11:   Edit PostDelete PostView Post/Check IP

Hi Richard Many thanks for your reply, I would say its only warm, ive used this to heat the car sometimes (as otherwise no heat) and if I turn it on it can stay on for some time without me breaking into a sweat), ive got an infa red thermometer so guess I could try that either side of the heater tap when hot and heat on, but as its intermittent am wondering if the heater pipes might be airlocked? Is that likely or do they tend to self purge? Many Thanks Andy
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 4
Registered: 4-2015
Posted on Sunday, 04 October, 2015 - 04:31:   Edit PostDelete PostView Post/Check IP

Ive drained and refilled the system in accordance with the earlier posts with a funnel to extend the height and run it for 10mins on defrost, defrost heat is now what I would call Hot 60+ deg, and seem to have heat in the car. Ill wait until its cold outside and see if it heats the car to a comfortable state if not ill report back. Ps I tested the the temp each side of the tap which is equal at 65+ deg each side so guess it must be opening ok.
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 558
Registered: 5-2015
Posted on Sunday, 04 October, 2015 - 10:09:   Edit PostDelete PostView Post/Check IP

On Shadows the heater tap is either on or off. The temperature is controlled by air blending not the tap.

The temperature either side of the tap will always be similar because if the tap is shut then no water flows either side of the tap and the tap get warm because because of conduction. 65c is not hot the engine runs at 90c. The rubber pipes dont lose that much heat. The tap must be open to get any heat. But it could be obstructed or adjusted incorrectly.

If the tap is in the return line then the heater will draw heat out and the return side will be lower temp.

The tap on a Shadow is known for sludging up. Its easy to remove and clean. Thus restricts flow and of course heat.

So if the Spirit tap is the same then remove and clean. If not disconnect heater pipe connect to water main and run water through with engine not running for an hour. And marvel at the amount of crap comming out.


My Shadow heater gets very hot quite quickly and has to be turned down even on frosty days 0c days. I should think a Spirit is the same.

Its ok to drain the coolant and put it back in after flushing with plain water. I like to add a neat litre of antifreeze as a top up when I flush. Filter the coolant with a cloth spread over the top of a bucket.

Use hydrometer to check antifreeze strength. Antifreeze hydrometers are about 3 quid. Also get one for battery same price. Very handy cheap tools. Note that hydrometers only work on glycolic antifreeze not methanol which you should not use any way.

And ----- thermostat is it present and is it working. It must work for the heater to work properly. The stats last well but there have been reports of safety plugs falling out. There is an after market thermostat. See tee one topics.

I am very fussy with cooling systems so much so that I devout a special service to the cooling system. Overheating the engine would probably scrap the car. The service takes all day. Main rad is removed and inverted and back flushed and so on. And of course while its out I paint it.

For flushing I turned on a lathe wooden bungs with domestic copper pipe in the centre for connection to a hose pipe.

Once a year I service the cooling system and every 3 years ( should be 2 ) new antifreeze.

Now that you know how to get rid of air locks it should be easy to flush.

Citric acid is sometimes used but I use a proprietary rad flush chemical but only on cars that are badly sludged up. If using rad flush follow instructions to the letter. Most involve lots of water to clean out the rad flush after.

Hoses. The hose clips are there to stop the hose sliding off not to stop leaks. The hose must seal with out clip at no pressure. Any leaks clean what ever hose fits to and change hose. Hose clips are often fitted with a 7mm AF size screw worm head. This is not for doing the clip up really tight. Its for using 1/4 drive sockets in restricted spaces. So just a nip is enough.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1390
Registered: 6-2006
Posted on Monday, 05 October, 2015 - 07:18:   Edit PostDelete PostView Post/Check IP

Sounds as though you may have had an airlock or sludge in the heater matrix.

For your info the 40 degree switch will not stop you getting heat. It will just stop the fans operating. A good test is to turn to max hot or max cold (a click an be felt). Once the fans are operating they should continue to do so when you back off the heat dials.

The heater tap can stick as well. Or not allow a good flow when ticking over and at higher revs.

Good luck with her :-)
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 5
Registered: 4-2015
Posted on Monday, 05 October, 2015 - 08:03:   Edit PostDelete PostView Post/Check IP

Thanks guys for the additional info, i had replaced the stat and backflushed the system twice but all was clear. Refilled with new RR / Bentley Coolant at 50/50 mix. Think it must have been airlocked at the heater matrix, Ill let you know how things go when I use her next, waiting for new brake pads at the moment.
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 6
Registered: 4-2015
Posted on Wednesday, 07 October, 2015 - 02:43:   Edit PostDelete PostView Post/Check IP

Still seem to have a problem at times, perhaps best to eliminate some items, I guess if the heat coming from the defrost is close to the water temp when hot then I assume that would eliminate or implicate the heater tap! My only other thought is whether i do need to initialize the board? If this were wrong would it put the flaps in the wrong place? Things work fine on cooling but not on heat. When testing with the rig from Flying spares it indicated the 40 deg sensor was faulty, ive changed that but wonder if perhaps it may have a poor connection or broken wire, is there any way to test this without the rig? Thanks Andy
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richard george yeaman
Grand Master
Username: richyrich

Post Number: 359
Registered: 4-2012
Posted on Wednesday, 07 October, 2015 - 05:12:   Edit PostDelete PostView Post/Check IP

Hello Andrew welcome to the forum I hope your troubles will soon be in the past sorry I cant help but there are those that can good luck.

Richard.
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 582
Registered: 5-2015
Posted on Wednesday, 07 October, 2015 - 07:40:   Edit PostDelete PostView Post/Check IP

On a Shadow. The water tap is either on or off. The tap is a Smiths design that is used on other makes such as Triumph. The tap as used by Truimph is variable because the heat is controlled by water flow.
This means that should the adjustment of the tap be wrong it is possible to have the tap only open a bit.

The heat is controlled by air blending. Hot air from heater cold air from AC or outside of car.

In cars with no AC and air blending heating there is not water tap. And the heater matrix and pipe work is also the pump bypass route. Also the heater circuit helps cool the engine. Eg Ford Cortina.

But with air blending and AC when the weather is hot the heater matrix needs to be shut off. Hence the on/off only water tap.

The AC is also a dehumidifier. This requires both heat and AC at the same time. And very effective us is too at clearing a misty screen.

Water tap heat control is not very controllable which is why air blending is used.

Your car is simply a AC and Heating system combined together and automatically controlled.

If the water tap lever is going full throw. Then check the air blending flap.

Pivots can get tight and cause flaps to jam and the servo carries on and bends the rod. They have dog legs to bend intentionally rather than snap something or burn up the servo.

This system is reliable but as with anything getting old and electro mechanical with added electronics theres a lot of minor faults that are differcult to find which stop the automatic bit working.

There is a modification I believe that stops air locks.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1391
Registered: 6-2006
Posted on Wednesday, 07 October, 2015 - 09:16:   Edit PostDelete PostView Post/Check IP

Andy, disconnect it. All the switch does is stop the fans operating before the engine water temp reaches 40 degrees.

This is so that when you jump in on a freezing day and ask for heat, you will not have an icy blast while the coolant heats up.

Asking for defrost overrides the 40 degree switch and allows the fans to run.

Do initialise the board. Do check the actuator levers above the board are moving.

Have any of the temp sensors been disturbed? front bumper ones?
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 588
Registered: 5-2015
Posted on Wednesday, 07 October, 2015 - 09:39:   Edit PostDelete PostView Post/Check IP

A lot of other makers use 40c as a milestone for things to start working such as temp gauges. Most climate control systems are like this they have sensors which are open until certain parameters are met.

The heater system on my Shadow is very good its the best I have had in a car. So given that RR don't go backwards the Climate control version is superb. My heater is very fast. On a cold and frosty its getting warm in 3 or 4 mins. And the amount of coolant means that later on in the day the heater is even quicker.

One winter week I drove the long way home so I could enjoy the heater.
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 7
Registered: 4-2015
Posted on Friday, 09 October, 2015 - 18:03:   Edit PostDelete PostView Post/Check IP

Hi Guys many thanks for your knowledgeable assistance so far.
So I did a test and am always getting almost as much heat on defrost as the coolant temp at the pipes, so assume that the heater tap is working and that the heat exchanger etc are not air locked??
So onto the 40 deg switch (not easy to disconnect at the switch as chargecooler is in way) so looking at the circuit diagram http://rrtechnical.info/sz/sz87/20kfantemp.pdf am I correct this is normally closed (engine cold), so if i disconnect the wire from pin one left side it should trick the board into thinking the engine is warm? Thanks Andy
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1393
Registered: 6-2006
Posted on Friday, 09 October, 2015 - 19:02:   Edit PostDelete PostView Post/Check IP

Andrew correct.

If it's easier, the wire (pink and black I think, but you have the diagram) comes to a connector near the engine ecu.

But . . . Are you getting fans operating when you Start the car, have the system set on high, dials both to red and white area and the engine warm.

Are you getting fans blowing but no heat??? VERY different faults.

The 40degree switch will not stop HEAT just the FANS.
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 8
Registered: 4-2015
Posted on Saturday, 10 October, 2015 - 04:31:   Edit PostDelete PostView Post/Check IP

Hi Paul
Thanks for the reply, i do get both (AT times) however its all a bit limp! low heat and low fan even when inside the car is cold (this morning). Think ill discon the 40 deg (just in case), thanks for the tip re by the ecu but im going to the board to test the resistance on the ext temp sensor. If not im guessing initialization procedure next???
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 9
Registered: 4-2015
Posted on Sunday, 11 October, 2015 - 06:25:   Edit PostDelete PostView Post/Check IP

Hi Paul Im just checking why you asked if the front bumper sensor had been disturbed, it is possible. Do you know where the connector for this is, ive located the sensor RH front bumper but cant find where it connects into the loom?
Many Thanks
Andy
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Andrew Radford
New User
Username: thequalitybuilder

Post Number: 10
Registered: 4-2015
Posted on Tuesday, 13 October, 2015 - 06:02:   Edit PostDelete PostView Post/Check IP

Im struggling a bit with checking the ambient sensor resistance as my ECU is wired differently to the best circuit diagram I could find (Upto 50,000 vin) mine is 66,832, is the wire likely to still be Red yellow at the board? If anyone has a circuit diagram for these later cars hat would be great?
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 1398
Registered: 6-2006
Posted on Wednesday, 14 October, 2015 - 20:45:   Edit PostDelete PostView Post/Check IP

Hi Andrew, that is the one that most often gets disturbed. Usually by paintshops.

They are often damaged, disconnected or poked into somewhere MUCH warmer than ambient. This can make the ECU think things are much hotter than they really are and cut back on hot air.

Various mounting places. They poke out of the wings behind the front bumper end caps, are mounted on the bumper bars underside, and early cars have them on the air filter intake under and behind the front bumper.

Will check the manual for colours later , just going out on a FTP.
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Andrew Radford
Experienced User
Username: thequalitybuilder

Post Number: 14
Registered: 4-2015
Posted on Friday, 27 November, 2015 - 21:52:   Edit PostDelete PostView Post/Check IP

Thank you Paul, it is in the front bumper on mine, it had been replaced and did not appear damaged at all however ive cut one of the wires as it goes into the loom to give full resistance which would make the ecu think its cold outside, but the heater tap is still being shut, even on red click. One thing, the header tank bottle never seems to get pressurised, there is no leak but the cap seems rather worn, would this affect the temp of the engine? and if so would that have an effect on the heating? If not maybe I need to get the test rig back and recheck? Ps you were 100% correct about it not doing the ice warning as I freeze sprayed it and got no warning.Again many thanks for your help.
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Todd Keleske
Experienced User
Username: toddk

Post Number: 31
Registered: 4-2017
Posted on Saturday, 29 April, 2017 - 14:08:   Edit PostDelete PostView Post/Check IP

Newby Searching Forums...2002 Azure new to me.
My HVAC ....Blows as should hot or cold only at the defroster level. Nothing from dash vents.

Will look at fuses, along with any other suggestions. Thx, Todd
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Dieter Jud
Yet to post message
Username: dieter

Post Number: 1
Registered: 8-2017
Posted on Sunday, 03 September, 2017 - 21:38:   Edit PostDelete PostView Post/Check IP

Hello,
I have a similar problem. Cooling works fine. Hot air only at the defroster.

I therefore tried to adjust the potentiometer on the micro controller board. This does not work, because someone has already tried this an he bent both potentiometers backwards, that the connections are broken. I replaced the 2 potentiometers with the same type.

Now I have to adjust the potentiometers as it is written in the Section C supplement (its a 1988 Spirit)from TSD 4700.

My question is, how it will work?

The instruction says for removing controller board: both 18 way plugs removed. Upper and lower blend flap disconnected.

The adjustment is now with removed controller board not possible, because there is no power to the board. Is it correct, that I have to install the board again and connect all 4 plugs to adjust the potentiometers. Then install the bridge, the power and watch the red LED on the board. Its not possible to adjust the board outside the car.

Or is there another mistake which can cause no hot air at both facias, only on the defroster?

Thank you for your help.

Best regards
Dieter

Chassis number SCAZS02BXJCX221xxx

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