Posted From: 220.127.116.11
|Posted on Monday, 22 November, 2004 - 07:49: |
Just returned from work after converting B72DA to negative earth with no problems (thanks for your help).
I noticed the temperature gauge was not working so followed the solid wire (with spring wrapped round thermo coupling?) and found this had been broken at some time. Is there a way of fixing this?
I also had a quick look at my fuel gauge that has never worked since owning the car. Underneath at the tank the top red wire has a live feed and when earthed to the body makes the green low fuel light come on. The brown wire at the bottom of the sender has now power and does nothing to the gauge when put to earth (don't forget its negative earth now). On modern vehicles earthing the tank sender feed or temp gauge feed makes the gauge go right over to the full or overheating red. If my gauge on B72DA was working should the same happen? I don't want to buy a fuel sender and find its the gauge. I tried to pull the gauges out of the dash but with no luck, it seems like an awkward thing to get at and I wanted to confirm it was faulty before removal.
Many thanks Mark
(Message approved by david_gore)
Post Number: 6
|Posted on Tuesday, 23 November, 2004 - 07:24: |
The temp gauge sender is the same as on many other cars of the period, the tube contains (I think) alcohol, and once the pipe fractures, the gas or liquid escapes, so replacement is your only option. Can't help with the fuel guage as mine doesn't work either.
Post Number: 7
|Posted on Tuesday, 23 November, 2004 - 09:38: |
Mark made a duplicate post on the BDC website and I have replied there as follows:-
The fuel tank and sump contents senders are both very similar and only differ in respect of the float linkages. Electrically they are both variable resistors going from about zero to about 75 ohms depending on the float level. All the connections are routed through the main cannection box on the bulkhead and if you temporarily disconnect one or other of the wires there you can verify different parts of the circuits. The changeover switch on the instrument panel connects the sump contacts sender and disconnects the petrol tank sender when it is pressed. Does the gauge show any movement when this switch is pressed?
Your change in polarity wll not, in itself, have affected the gauge in any way since it is a simple moving iron instrument where the position of the pointer depends on the relative magnetic strength of two separate electromagnets. This means that the pointer position is also independent of voltage.
If you do decide that the gauge is faulty then it can probably be repaired but don`t just take it to pieces to find out since some of the screws hold the internal coils in a particular position to make it work correctly. There is an article in one of the BDC Reviews which covers the matter in more detail."
I know which issue the article is in because I wrote in the the days before there were any websites. Can I help?
Post Number: 3
|Posted on Thursday, 25 November, 2004 - 09:22: |
Thank you for your replies. I will have a look at the weekend at the junction box etc. I might stand a better chance understanding the wiring on my car now its negative earth. Will report back my findings.
Post Number: 10
|Posted on Saturday, 27 November, 2004 - 02:14: |
I have a correctly functioning temperature gage (just tested it in boiling water) that is for a Mk VI-R type car. If you want it email me at firstname.lastname@example.org. I have no idea what it is worth, but I am sure we can figure that out.
Post Number: 66
|Posted on Tuesday, 12 July, 2005 - 10:11: |
Hope someone can help.
I need a temperature gauge desperately on my car due to the nature of the work I do (weddings)
Has anybody fitted an electrical temp gauge?
I don't want to use the original one in the dash as removal of the wires etc looks a bit awkward and time consuming. I plan on fitting two separate gauges, one for the temp and the other for fuel. Both of my originals do not work. I will mount the new electric units under the dash by the steering wheel.
Has anybody found an electric temp sender that will just fit in the block without too much fuss?
Any help would be really appreciated as I seem to have exhausted every other avenue. Many thanks Mark
Post Number: 220
|Posted on Tuesday, 12 July, 2005 - 12:53: |
With the fuel guage, check the sender unit in the tank first as that may be at fault.
With the temperature guage, whilst it's desirable to get the original fixed eventually, VDO makes a temp guage that has a sensor that you can fit into the upper radiator hose. Very simple and it should keep you out of trouble until you eventually get to the original.
Post Number: 18
|Posted on Thursday, 14 July, 2005 - 01:45: |
Speedograph Richfield (in the UK) will repair your gauge at a reasonable cost. Check on turn around times before posting off. My last repair with them was a combined oil pressure/water temperature gauge on my PIII - took about 10 days and cost £71.
Based in Nottingham.