Mk1 Instrument cluster

Every now and then I lose power to the rev counter, fuel and temp gauge as well as led lights. Although it still lights up and clock works fine. They will stay dead for a while and then either come back to life while driver or work normal when I start the car next day. I'm thinking it may be a relay breaking down so would that be in fuse box? Other then that no clue unless it's under bonnet? Gotta love electrical gremlins.
Any ideas? 

Replace the 10V stabilizer, it is a FA7810-ate.
If you buy it at an electronics supply or on line from www.mouser.com they are about 75 cents.




If you order it from the dealer it is about 45 dollars.

Add a new ground to pin 2 (brown ) to your cluster as this will only help you, splice it in behind the connector (wire side) and use a sheet metal screw to the frame behind the "X" brace.

3m wire splice works good.




Carefully remove the shroud from the main connector, extreme caution to lift the mylar off the tongue, then add  one piece of electrical tape on the pad side of the tongue of plastic reseat the mylar and the shroud.




The 10V stabilizer can effect all the above that you mention if it goes wonky the wrong way, also the ground pin.  Now the addition of the tape to the tongue will tighten the connector pins to the mylar pad.

There goes my simple fix idea then didn't really want to strip the dash board down. It may be just a bad earth. 

Then you don't want to hear that your Mylar flexure board may have a broken run and that you may have to
Back feed voltages or ground to it via the 10V stabilizer.

The Fixes I show up above aren't that hard to repair, fix, or redo.  Easier than back feeding, and a lot easier than repairing the Water Temp gauge for flaky solder joints.

It could be as simple as the adding a piece of tape on the tongue of the connector.

But you asked what is the fix, and well all 3 are the fix, or back feeding the voltages when there is a bad mylar run.

before you go too crazy, if its a MFA type cluster check the earth for the clocks to the side of the head. its the brown/white wire.

Also worth a look at the ignition live feed for the cluster, its the smaller black wire coming out the back of the ignition switch

best to start with the simple checks then work your way up

i am having the exact same issue , did you manage to fix yours?

Did you find out what was wrong ??

Also having this issue, anybody ever get any closure? Thanks

If my, very old, memory serves me well there is a voltage regulator somewhere that's a piece of cake to replace. Remember doing it when I had Mk2 Sciroccos coming out of my ears. Think it's fitted on the alternator but don't quote me for reasons explained above.
The instruments mentioned above are sensitive to voltage fluctuations. A lot of the other stuff isn't.

There’s a voltage Reg on your alternator that controls the output voltage to charge the battery.
There is a 10V stabiliser on the back of the clocks.

I had issues with my clocks I found intermittent problems went away when I tapped the clocks or top of the dash.
This showed poor connection to the clocks on the multiplug and blue Mylar film.
I cleaned the copper contacts and padded the tongue the foil fits over this gives a better contact.
Never had an issue since.


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