MK1 cab instrument cluster intermittent

Hi there, I e got a g reg 1.8 clipper, having issues with the instrument cluster, when I first start the car from cold everything works, revs,Speedo, fuel guage illuminations, just everything works as it should. Then once the car has warmed/got hot if I turn it off and back on again then all I get working is the Speedo(I know this I cable driven).  Then the other day I left the car outside and it was a hot day and the cluster wouldn't work when starting I'm assuming just from the heat. Parked it in the garage overnight and everything was working fine again in the morning once cool.

Look into Plumping your connector, and adding a new ground or I should say an additional ground to Pin 2 the Brown wire with a wire that is tied directly from the Frame at the rear of the X cross behind the Cluster to the Brown wire.

https://www.volkswagenownersclub.com/threads/improving-your-cluster-connections-and-ground.24949/?post_id=753377#post-753377
 
As a first Course.

I've already put the extra layer of tape to bulk the connector and done the earth, any other ideas out there?

Did you test Pin 2 to pin 14 (black) wire for Battery voltage at key in and run, should be 12.5-13Vdc to pin 2 Brown.

So is pin 14 (black) the live feed? And pin 2(brown) the earth.
I did not check either tbh I just added an earth cable

yes.  black is +12 brown is ground or earth.

Sorry for slow update, work getting in the way. So I have now tested it, got the clocks to the point they stopped working on me, checked the connections, bent them down for better contact
Tested the power(black) getting approx 12.4v
Checked the earth(brown) getting a good earth with the body of the car.
I'm sure once the car has cooled down(or rather the clocks) they will start working again
Any other ideas would be greatly appreciated

Any help greatly appreciated guys

The only heat sensitive item is the 10V voltage stabilizer, the Water temp gauge, the Fuel gauge, and the  Mylar Circuit.

I have had the copper contact on the mylar separate from the mylar, and re-connecting them scoots the pad away, causing a iffy connection and intermittent clocks.

So what's the solution, new clocks? Bearing in mind I don't know what the mylar is

Mylar is a type of flexible plastic - on which a circuit can be printed. It's worth examining the flexible PCB very closely to look for evidence of cracked tracks, damaged contacts, etc

Might be easier to change the clocks by the sound of it, anyone got a set for sale??

Contact Dan Ferguson at VW Northwest. He may be able to sort you out. 

VW Northwest | Poulton le Fylde

So I have changed the 10v stabiliser and put in a new digital clock, same issue as before, when car gets hot inside be it from heaters or a hot day the revs, temp and indicator illumination section don't work but the digital time clock keeps working.any help really appreciated

Sounds as if your Mylar is separating the lamination or cracked

It wouldn't hurt to back feed the Tach or one of the temp gauges as that will usually power the other two.  I have had to do that on one set of my clocks.

https://www.volkswagenownersclub.com/threads/90ish-cabriolet-mylar-repair-for-10v-stabilizer.60258/?post_id=531266#post-531266

Hi briano, any pointers on how to do that? Any pictures or info on what needs to be done? Thanks

Read the Link.

Hi briano, so by following your tutorial above  in the main my clocks seem to be better than before(no more cutting out) but I seem to have developed a new issue, the fuel guage no longer works. I have tested the guage and running power to it it goes up to full, I checked the wire at the back of the clock and no voltage, and have checked the wires at the fuel pickup/sender and am getting approx 0.24v across the wires there.
To me it seems there's not enough power to activate the guage but I have no idea where to check now.
All fuses fine
1.8 petrol cab g reg
Amy help appreciated

Does the water temp gauge work? Yes, then we need to test the whole run.

Take the Sender connection off of the tank connection.
Take a 9V Dc battery and place the +12v side on the Violet wire, and Ground to the Sender cover, and or the Brown wire in the connector.

IIRC the gauge should move with the key off, if not then place the key in the tun position

If the Gauge moves then it is your sender, if it dosen't then it is a broken connection between the Sender and the Gauge.

You can use the 9V battery trick on the back of the fuel gauge to verify the gauge works.

If the Gauge works then you then have an issue between the connector and the gauge.  You may have to bypass the mylar run .

Knowing where the issue is is the best thing to finger out?

repairing your sending unit.
https://www.volkswagenownersclub.com/threads/repairing-your-fuel-sending-unit.78890/#post-600458

Verify that your 10V stabilizer is getting the 10V to the fuel gauge. if not then you may have to back feed it.

The stabilizer places 10v to one side of the fuel gauge, and the violet wire on the connector allows the gauge to get sender ground.

Ok so before I saw your reply I had already put 12v to the back of the clock where the purple wire comes in and the guage went up so does that mean the guage is working ?I'm not getting any voltage reading from the plug on the sender unit, should I ? I am getting a ground from the brown wire at the sender.
If I just run a wire straight from the purple wire at the sender to no3 at the clocks would that show if there is a break in the wire if it all starts working?