Rev meter, mfa and water temp dials not working...

Hi just bought a mk1 golf, and I love it. It has a few problems which I am trying to sort out though.

When the headlights are turned on, the rev meter, mfa and water temp dials stop working or give weird figures. However when the headlights are off, the mfa and rev meter work fine.

The water temp however goes up and down like a yoyo.

What do you guru's reckon? I have tried to find a thread that deals with a problem like this but to no avail.

All help much appreciated.

Thanks

I have this problem, been suggested that it could be an earth lead missing from the rocker cover to the bulkhead (near the coil i think)

My Golf hasn't been together enough to try it yet though.

Hopefully someone else can confirm that this advice was good, it drove me craZy for the short time i was driving mine.

Sounds like a classic poor earth connection, pop the bonnet and whilst looking at the engine there should be an earth lead connected to the far right camshaft cover stud, it will probably still be there, just the bit of wire that should be connected to it has snapped and is hiding in the oil down by the side of the head
Have fun, hope that helps!

Do you know where the other end earths to normally?  I've had a quick look and not found one.

It goes into the wiring loom and through the bulk head somewhere under the servo.

Cheers, I'll have another look at mine. thought I was just after a bit of braided strap to the bulk head.

I think that goes to the coil. Look for a brown wire hanging loose under the servo somewhere.

Mine did a similar thing.

Found a piece of wire 2" long attached to the rocker cover but couldn't find the other end.

If you look directly behind the lump you'll see a big pack of loom.  My cable had broken inside the loom and I only found it when I stripped a couple of inches of loom sheath back.

Cheers

Mat

It's actually the instrument cluster earth that for some reason vw decided to route out into the engine bay.  I suppose you could pull the cluster out and tie the earth straight to the body without going out into the engine bay.

Cheers

Mat

It gives the MFA a better reading for the oil sensor and helps with the water temp sensor, obviously you wouldn't want the buzzers going off all the time so they tried to make the return path a bit more robust, crazy germans :-)

Could anyone possibly take a photo of the earth wire that connects to the cam shaft cover stud and take a pic of where it goes because I can see no sign of one.

Thanks