Temperature gauge needle and blinking light

[Zimbok]

Hi, I have a 1990, 2.1 DJ van.

I had some wiring replaced in the engine bay a few months ago and whilst the van is running fine, a legacy of the work done is that a wire or two seems to have been wired up incorrectly (or maybe not!). I have changed the Coolant level Sensor and the Coolant Temperature Sensor and also the no 42 relay as well but none of these has worked.

If I turn the ignition on (but don't start the engine) the light will flash a few times and then stop and the needle will not move from its position on the left.

If I start the engine (but don't drive) the temperature gauge needle goes straight over to the right (as if overheating) and the temp light will flash continuously and it will stay there as long as I have the engine running.

However (and I have only noticed this today) when driving if I coast with no accelaration, the flashing will stop and the needle will go from right on the gauge to the left i.e. from extreme right to extreme left . As soon as I accelerate though the needle will go to the right again and the light with resume flashing. This also happened when I stop the van e.g. at traffic lights, the flashing will stop and the needle goes to the extreme left. As soon as I move off back to blinking / max temp gauge.

It seems the blinking light / needle have minds of their own. How does accelerating the van have an effect on the temp gauge blinking light / needle?

Most puzzling. Any ideas?

Cheers.

[neilh]

I had a problem a while ago where the light would not stop flashing. Checked the coolant level, and level sensor and all was OK. I traced it eventually to the printed circuit board behind the dashboard where the copper(?) contacts were corroded. Cleaned them all up with some very fine abrasive paper (they're quite delicate) and problem solved.
May be worth a check?
Cheers
Neil

[Zimbok]

I had a problem a while ago where the light would not stop flashing. Checked the coolant level, and level sensor and all was OK. I traced it eventually to the printed circuit board behind the dashboard where the copper(?) contacts were corroded. Cleaned them all up with some very fine abrasive paper (they're quite delicate) and problem solved.
May be worth a check?
Cheers
Neil

Cheers both for the comments. Tried the above as well. Bought some liquid type stuff from Maplins to bridge the copper contacts if I had encountered a problem when I opened everything up. However all looked fine and I cleaned also with fine abrasive as suggested. Still nothing.

Still puzzled by the whole thing especially the blinking stopping and the needle going back to left when I am coasting / stopped. How is that linked to acceleration? I am waiting to have it looked at professionally as I am pathetic when it comes to electrics (in fact mechanics and everything else close behind!) but am way down on the waiting list unfortunately.

[neilh]

I've been having a think about this and I remembered long ago when used to work in the motor trade that we used to sell dashboard voltage regulators for the gauges and lo and behold there some forums on here that discuss the regulator, and associated problems if it fails.
Also see this link on the Wiki
https://club8090.co.uk/wiki/VW ... uel_gauges

Hope that helps

[Zimbok]

I've been having a think about this and I remembered long ago when used to work in the motor trade that we used to sell dashboard voltage regulators for the gauges and lo and behold there some forums on here that discuss the regulator, and associated problems if it fails.
Also see this link on the Wiki
https://club8090.co.uk/wiki/VW ... uel_gauges

Hope that helps

Cheers Neil. I have been looking at some posts as you suggest and a quote on one thread I read is "there is a voltage regulator to the fuel gauge and temperature sender which can also fail, but in which case your temp gauge would also not work". Mine is the reverse insofar as my fuel gauge does work and the temp gauge is dodgy. Would it be the case that if there is a problem with the voltage regulator both the fuel gauge and temp gauge wouldn't work.

The cost of the regulator is about £2 on Ebay and for that price I think I will change it and see what happens. I can take the dash pod etc off blindfolded and in the dark no problem. I seem to have done it so many times now!

Cheers.

Just read the link you gave me (doh!)..."If only one gauge is inoperative, regulator is not defective. If both fuel and temperature gauges are inoperative, voltage regulator may be faulty or have a bad ground connection."

[andyb]

Have you had a look at relay 43 ? can be the culprit.