Temp gauge and rev counter not working.

[airhead]

Just a couple of the many electrical problems to sort out but Id like to get these done first.

Firstly, its a Golf Mk2 GTD, 1991.

So far Ive checked the connection on the bottom of the instrument panel. It seems fine. Also, I gave the temp gauge some power directly and it went up, so with the temp gauge, its not the gauge thats the problem. I'd say the same applies to the rev counter. I checked all the tracks on the circuit and there was none broken. The whole thing looked very clean actually. So this leads me to believe the problem is elsewhere. Now, my question is this. Where do I start? Where do these gauges connect to and where do I need to check?

If anyone has access to a wiring diagram, it would be a great help as well. I haven't managed to get a workshop manual yet, so I'll be going on the help of you good people and my own knowledge.

[burn_your_money]

For the tach, start at the alternator. Check the red/black wire at the alternator, then follow that wire and the blue wire along to the connection right by the battery.

For the temp gauge, there is a sender on the side of the head, and one on the front on the plastic coolant outlets. If you have AC you'll have a third one. Try swapping the 2 temp ones around. The sensors are very close to the same and it will work. The AC one has a green wire going to it, just leave that one alone.

If that does solve the problem you need to replace the sender otherwise your glowplugs will stay on for the maximum amount of time, every time regardless of engine temperature.

I'm going by memory on the wire colors so I could be wrong

[airhead]

Thanks. I actually sorted out the problem with the temperature gauge. It was a broken wire. Isn't it nice when things are that simple?!

Anyway thats one of a myriad of electrical problems to sort out (you think it being diesel would at least help!) and I still have the tacho to sort out. Ive no dashboard lights either, but thats just cause I need to replace the bulbs. My electric mirrors aren't working either. Also, my passenger door will open with central locking but wont close. One of my headlights is darker than the other too. If anyone has any further insight, I'd be happy to hear it!

To give a further lowdown on the rev counter, here's what Ive discovered. I knew the alt belt was slipping anyway, but only from time to time. I didnt think that would affect the tacho, but very occasionally when the belt slips, the tacho jumps slightly. I checked the connection on the alt, and it seemed fine, just a bit dirty. I was going to start by cleaning the terminal and putting on a new spade connector on the wire to make sure everything is fine there. Is it likely that it would be the alternator itself thats the problem? 

[Vincent Waldon]

The tach is driven by a signal from the alternator... so if the alternator slips the tach will jump.

Or am I not understanding what you're saying?

[airhead]

Yeah I mean it stays on zero all the time and sometimes when the belt slips it jumps but just goes back to zero. Sorry, I should have made myself clearer.

[vanbcguy]

Have you tried cleaning the W terminal connector?  Mine was oxidized and my tach was going totally nuts.  Gave it a little rub with some emery cloth and bam, perfectly working tach.

When it was going crazy it would read at idle and low engine speeds but wouldn't ever go over about 2000 RPM...