| Author | Message | ||
     Jason Pfeiffer Experienced User Username: jpsnaggs Post Number: 37 Registered: 7-2006 |
Ugh. So, I got the car back today. The starter relay needed to be replaced and I had the oil changed as well. but, now we have another problem. Appears that when the car is off, and key removed, something is not shutting off. Some of the dash lights on the info center (i.e. the break pressure and oil lights) flicker on and off a bit, and when you press the gas peddle, the spedo moves up, and the gas gage moves as well - remember the car is off - What to do? The mechanic says I will just have to bring the car back, and leave it for awhile while they fiddle... The BIG problem is that this drains the battery, so after a few hourrs of sitting, the battery is dead. The remedy for this temporarly is to shut the battery off in the trunk when the car will be sitting overnight. The mechanic seems to think it has something to do with the starter. I am starting to get really frustrated. Its not the money as I have not put that much into the car to date, however this is getting frustrating | ||
| David Gore Moderator Username: david_gore Post Number: 659 Registered: 4-2003 |
Hi Jason, Remember the movie "Gremlins"? Looks like one has taken up residence in your car and evicting him/her can be very frustrating especially if the auto electrician has not touched a R-R/B before. You end up paying them to learn "on the job". Suggest you get the auto electrician to insert an ammeter into the electrical circuit at the battery terminal and then remove all fuses/circuit breakers and see if there is any current flow. If not, activate one circuit at a time with everything switched off and look for current flow - if you get current flow, you then have to test each part of that circuit till you find the short. Disconnect the circuit before activating the next circuit. If you get current flow with all circuits disconnected, remove the ammeter from the battery and insert it into the circuit at the battery lead termination point in the engine bay [on Shadows, this is the starter motor terminal] however I have no idea where it is on a Spirit. If no current flow recorded, there is a short from the main battery lead to the chassis between the battery and the engine bay however the symptoms you describe suggest this will not be the case. Help please someone - does the Spirit have diodes in the wiring like Shadows? If so, this could explain the flickering lights due to faulty diodes. Also check the alternator diodes by disconnecting the alternator leads - if the diodes are faulty, they can cause the battery to go flat when the car is switched off. Also make sure the earthing lead from the starter motor mounting bolt to the chassis was reconnected after the work on the starter - you cannot rely on the starter motor earthing through the engine block like most ordinary cars - this has been a source of problems with the Shadows. Some detective skills will be needed to get to the bottom of this and it will be a challenge to your patience and good humour. Just remember our good friend Murphy - "the more trouble you have in the beginning; the less you will have later". | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 613 Registered: 9-2004 |
Long shot without testing the car. Maybe a diode failure within the altenator giving feedback! | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1103 Registered: 4-2003 |
Indeed there are many diodes in all SZ cars. There is a diode block in the fuse panel which controls a multitude of functions. A blown diode on this board can backfeed to the instruments in the manner you mention, but only in a most bizarre type of failure (see the workshop manual on this site !). The combination of failed diodes to cause this is unlikely, particularly if the car behaves when running. Having said that, your diodes are living on borrowed time after 20 years, and should be replaced to eliminate any slight chance that one is faulty now or in the coming years. The easiest and quickest thing to do is to remove the diode board and replace all the diodes. Then try it out before spending too much time on diagnostics. Use 1N4001, 1N4004, 1N4007, any other 1N400x, or EM513. They cost a few cents each from an electrical wholesaler, so buy a hundred. If unsuccessful, then the master (ignition)switch is practically the only other possibility. If it is full of grit this problem is known to arise. They are repairable with care. They usually only ever need opening up and cleaning out thoroughly, lubricating with sewing machine oil, reassembling and refitting. A bad alternator diode cannot cause this effect. A very badly fried regulator could conceivably cause this, but especially if the alternator functions properly it is an extremely remote possibility. | ||
| Jason Pfeiffer Experienced User Username: jpsnaggs Post Number: 38 Registered: 7-2006 |
A couple of things, I have just had the alternator rebuilt about 2 months ago - and remember we just replaced the starter relay - maybe the car got mad or something  I have a feeling this is going to be one of those things that costs alot to diagnose, however will end up needing a fuse replaced, or something cleaned. And the car does behave great while started. You do think they will be able to figure it out eventually correct? (Message edited by jpsnaggs on October 12, 2006) | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 97 Registered: 9-2003 |
Hi Richard, What various sample symptoms arise that would indicate specifically the diode block in the fuse panel? Is it identical and in the same place in the 20,000 series cars? How are the diodes replaced into the block? Thanks, Larry | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1106 Registered: 4-2003 |
Larry, The diode board is a small plug-in printed circuit board located behind the fuse panel chassis. For 20000-series cars I have attached a photo. It is necessary to undo the chassis securing screws (takes seconds) and lower the chassis a little as shown. Unplug the two connectors, remove two screws, and the block is free. Diodes are easily replaced in minutes using a hobby soldering iron on the bench. In the attachment, I have marked the most common diode to fail on a 20000-series car. When that one fails, the interior lamps do not operate by opening the driver’s door, whilst all other door switches work the lamps fine. The inductive load gives this diode a particular jolt every time you close the driver’s door, and has a life of 20-40 years. Pre-20000-series cars have an additional diode block with cooling fins to control the fan speed (later cars use a passive resistor block for the same purpose). These power diodes are cheap and replaceable, whereas a new fan speed diode block is sold by Crewe for about $500. Other common diode faults relating to the diode block shown cause stalling on idle when the compressor kick in (no idle boost solenoid action), various climate control malfunctions (particularly inoperative flaps), warning lamp malfunctions or no test function, and various others too. There may also be several types of fuel injection or ignition imperfections due to failed diodes. That’s why I suggest they all be replaced at the slightest hint of a diode problem. I have also used additional diodes on the slow window remedy modification ,and three for headlamp dip relay circuit (my headlamp dip relay only toggles with the headlamps turned on now. Flashing the headlamps lamps doesn’t change the high beam status until the headlamps are turned on – very useful so you know which beam will come on when you need the lamps on a sunny day to drive on the highway here). The same diodes may be used on all cars since 1965 based on their physical size as follows: In the picture, you will notice two diode sizes. The small ones are 1N400x/EM513 (1A, DO-41 package), the same size but superior to the originals, and the larger ones are equally generic, a 1N5400-1N5408 1n540x type (3A, DO-201) package will do there as it again is of the correct size with superior characteristics. With a negligible price, diodes are not worth the effort of diagnosis. If in doubt, chuck ‘em out !  | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1107 Registered: 4-2003 |
ps the diodes I have suggested should outlast the originals by a factor of five. | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 98 Registered: 9-2003 |
Thanks Richard. The diagnostic info helps the thought/solution process. From what you said above, it reminds me that I don't notice a difference in speed between the climate control AUTO setting and HIGH setting specifically. There is a fan speed relay that is fine, and about 10 inches away on the firewall is sort of a finned unit that I thought had something to do with this. Is this what you mean? How do I test it or be sure that it is the problem? Also, when I replace the diodes, I should be able to not worry about them for at least 100 - 200 years? Larry If so, I'll inform my parrot. My Amazon is expected to be around then. Larry (Message edited by Larry Halpert on October 14, 2006) (Message edited by Larry Halpert on October 14, 2006) | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1108 Registered: 4-2003 |
The finned thing is the fan speed resistor block. It is a resistor array in a heat sink. The four relays closest to it switch the array in binary to achieve 16 fan speeds. If one resistor is dead, then the fan will stop for much of the desired range. Go to the 20000-series climate control (HVAC) section of the manuals to see the schematics. The resistor block may be removed by undoing the two retaining nuts and pulling the plug. Once removed, if the continuity between any of the leads is more than ohms (ie not kilohms) then one element is dead. A new block costs around $700, but the old may be repaired using.... POWER DIODES ! Maybe I'll start a new thread as this is wandering off topic, and I have some tips and pictures on repairing the 20000-series HVAC microprocessor controller. .  | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1109 Registered: 4-2003 |
and yes, Larry: improved replacement diodes should last indefinitely. Likewise, a rebuilt coolant level amplifier with new transistors and diodes on a Silver Shadow will far outlast a replacement unit. The same applies to a wide range of discrete-component controllers on Silver Shadows and SZ before they went mad on using microprocessors: dashboard dimmers, airconditioner servos, ice detectors, interior lamp timers, cruise controls and so on. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 675 Registered: 9-2004 |
Don't know if your prob got sorted? Been thinking, workshop practice! Do check the earth resistance between the engine and chassis and the computor and engine. Run test wires between points to confirm. Two computor earths coloured pink and black. Failings like the above will somtimes get the computer in a mind of it's own. | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 160 Registered: 9-2003 |
Well, it only took 8 years, but I finally took the fan speed resistor block out as I've always just had one low speed on the low setting, with auto and other settings not giving me faster fan operation. If you are there, Richard, I connected my new multi-meter, looking at the resistor block plug with black connected to the top left pin of the 3-row, and connected the red connector to each of the other pins. The meter ohm setting was "200", not the other numbers with a "K" or an "M". You wrote "if the continuity between any of the leads is more than ohms (ie not kilohms) then one element is dead." My readings on the 4 pins was 0.6, 2.2, 0.3 and 1.2 My simplistic explanation is so I do the test exactly right. Do any of these numbers indicate a "dead element"? Thanks, - Larry | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 161 Registered: 9-2003 |
Well, another question. Fan speed relays 1-4 all are operating, though I notice different voltages at different pins on the relays - from 7.5 - 11.5 volts. This happens with everything set to high, demist, (or any setting). But, the voltage coming to the blower motors is about 6.6 volts, which explains my low fan speed. Are the fans supposed to blow at high speed when all the relays are energized, or when none of the fan speed (1,2,3 & 4) relays are energized? Thanks, - Larry | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 163 Registered: 9-2003 |
Nice brand new shiny OEM 122 relays, and I get 11 volts at the motors now, which is a bit better..  |
