Red temperture warning light with a twist

[newkid]

This has me totally confused now so hoping you can help. Removed relay 43 just to double check it was the correct relay. Upon refitting it while we order a new one and then testing the system the red led now flashes everytime the ignition is turned on. The light doesn't stop flashing but here is the strange part, if put the headlamp switch onto position 2 (headlights on) the red led stops flashing and stays off. Still have the same error when i unplug one of the wires on the coolant level sensor and it restarts the red led and shoots of the hot scale side.

[MidLifeCrisis]

That sounds a lot like a problem with a bad ground connection (and it also sounds very weird!??!)
Have you checked to make sure that the coolant gauge has a good ground signal going to it.
You'll need to identify which of the three pins at the coolant gauge is the ground and then temporarily connect up a good ground wire. Would you be able to do this??

[newkid]

That sounds a lot like a problem with a bad ground connection (and it also sounds very weird!??!)
Have you checked to make sure that the coolant gauge has a good ground signal going to it.
You'll need to identify which of the three pins at the coolant gauge is the ground and then temporarily connect up a good ground wire. Would you be able to do this??

I can do grounds if I know which one im connecting to, my wiring knowledge is limited to sound systems unfortunately.

[MidLifeCrisis]

If you have the same dash as mine (i.e. no rev counter) then the ground is the one pictured (with the red circle around it);



If you have the rev counter then I think the layout is different.

[newkid]

Tried the above, didn't stop the led flashing.



The one circled in black did stop it when earthed, soon as i removed the earth it started flashing again, one circled in green made the needle go of the gauge. Same thing as with the lights, if i put the hazard lights on, it also turned the led off and stayed off till the ignition was next turned on.

[MidLifeCrisis]

The one circled in black did stop it when earthed, soon as i removed the earth it started flashing again, one circled in green made the needle go of the gauge. Same thing as with the lights, if i put the hazard lights on, it also turned the led off and stayed off till the ignition was next turned on.

The black one is the 10V supply to the gauge so grounding that would effectively remove power from the gauge (and also short circuit the voltage regulator to ground so probably best not to do it!!
The green one is the signal from the coolant temp sensor (and indirectly the relay 43) - so grounding that is the equivalent of a very hot reading from the temp sensor - so needle should go full right (hot) and the LED should flash.

Can you try pulling the 43 relay out and seeing how the gauge behaves with out it in place - maybe go for a drive and see what the needle does; try out the headlight/hazardlight thing - see if that behaves the same. maybe then ground the green terminal on the gauge and see what happens ....

(Your fault has me a bit stumped - its going to be something weird like a loose ground, loose power,but my money is still on a dodgy 43 relay (or perhaps the wiring to it?) that is making things behave strangely)

[newkid]

The one circled in black did stop it when earthed, soon as i removed the earth it started flashing again, one circled in green made the needle go of the gauge. Same thing as with the lights, if i put the hazard lights on, it also turned the led off and stayed off till the ignition was next turned on.

The black one is the 10V supply to the gauge so grounding that would effectively remove power from the gauge (and also short circuit the voltage regulator to ground so probably best not to do it!!
The green one is the signal from the coolant temp sensor (and indirectly the relay 43) - so grounding that is the equivalent of a very hot reading from the temp sensor - so needle should go full right (hot) and the LED should flash.

Can you try pulling the 43 relay out and seeing how the gauge behaves with out it in place - maybe go for a drive and see what the needle does; try out the headlight/hazardlight thing - see if that behaves the same. maybe then ground the green terminal on the gauge and see what happens ....

(Your fault has me a bit stumped - its going to be something weird like a loose ground, loose power,but my money is still on a dodgy 43 relay (or perhaps the wiring to it?) that is making things behave strangely)

I will try all this in 2 weeks, unfortunately my mum is away home again as she lives 100 miles away and had to go back for work. We have ordered another 43 relay of ebay as when we called VW its an obsolete part apparently. Also emailed brickwerks for another themostat as i think the new one mum ordered from justkampers opens to slowly. Van goes to half way between the red led and max when first driven for a few miles, then drops back to the normal position and sits there perfectly. Have read that brickwerks are the best for parts so we will be using them from now on.

Hopefully the 43 relay does the trick but I will report back as soon as Ive tested the points youve mentioned above.

Thanks for your help so far, this is by far the best forum I have ever used.