Rev counter, MFA and temp light not working

Hi I own a 1990 mk2 golf GTI 8v. Recently the rev counter stopped working, I could not change the MFA from the clock and the coolant warning light wasnt working. I initialy suspected the voltage regulator on the back of the clock cluster but once changed this made no difference. While doing this it started working again but intermittently. To me this seems like a short. I followed the red/black wire from the starter motor all the way to the bulkhead and there didnt seem to be any areas where it could short. Should I be following any other wires or look in other places. Thanks

 

Thanks rubjonny I gave this a go at first because I was unsure if it had blown but wiggling it around did not help.

 

@oscar fuller if you have no look with this and you've got a MotorMeter cluster its likely its failed internally. If you drop me a PM or e-mail in my signature I can sort out a repair for you!

 

Thanks Nate its a VDO cluster and is fairly new I had a look at the PCB and it all looks clean nothing seems to have been burnt out.

 

Its just stopped working again!!! Is it worth looking at the circuit behind the fusebox?

 

Ahh okay, could also be dry joints although I've never seen that happen with a VDO. Hopefully rubjonny suggestion sorts you out!

 

Just tried that this morning and I am unable to change the MFA from the clock in any way. Had a look at the loom that goes to the clocks and it all looked ok but was unable to follow it all the way into the bulkhead. I have sourced a spare PCB that might work but these clocks were new!!

 

Yes its a CE2 that sounds promising how do I check the live feed?

 

Got into the back of the fusebox the U1 wiring block looked ok no visible damage, is there an easy way to check that the wire is live? Also trialled another PCB and voltage regulator with no luck but was getting very high voltage readings on the pins of the voltage regulator.

 

What voltage are you seeing? You should battery voltage on one of the outer pins and 10 volts on the other. The centre pin/screw is ground. If you do take it apart just double check that it actually has a VDO board internally and not a Motormeter one as they are interchangeable

 

Thanks for this. took the blue pcb off the back of the clocks and all of the pins were ok. One of the resistors in the blue pcb is a bit dark but I tested it and it was ok. I took a voltage of 12.4V for the black wire to U1/4 and it was the same at the cluster end. Its a mystery to me why it isn't working.

 

for the voltage regulator the voltages I got for pins going left to right when you are looking at the back of the cluster I got 16.5V between 1 and 2, 12.4V between 2 and 3 and 4V between 1 and 3. When taking it apart the clocks did look like a VDO but I am not entirely sure of the difference between them

 

I suspected it was the voltage stabiliser and replaced it with 2 other used ones. They may all be broken but I thought that was unlikely. I was unable to have a look at the back of the circuit board to confirm weather it was VDO or motor meter because there was a red glue/clay fixing it into the housing and I did not want to damage it. I have found a cluster that isn’t too expensive that I’m going to buy and see if it works then but I would prefer not to.