Instrument cluster electrical problems

1.8 GTi instrument cluster electrical issues…..

Pretty much non of the dials on the cluster work accept for the Speedo and the oil light, indicator light, battery light and full beam light.

The rev counter does work when the car is stationary but as soon as I move it stops working, when I turn the headlights on the LEDs dash lights turn off making it impossible to see the speedo at night.

How can I fix this? Baring in mind electrical work is my weakest point so will need explaining thoroughly.

Also The LCD display only shows the time when the car is off, soon as i turn the ignition the screen displays random patterns when car is turned off the clock then resets.

I'm thinking maybe an earthing issue or the 10v stabiliser problem is I don't know to fix any of these issues.

Just to confirm these are the parts not working - Fuel gauge, rev counter, temp gauge, shift light.

If someone wouldn't mind explaining to me in simplified terms that would be really appreciated, I don't mind adding another earth cable but I've got no clue how to do so!

Any help is greatly appreciated!

Have a read through this document, it may assist you. 

https://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=electrical-faq_2%2Fmfa-operating-guide-and

The easiest to check will be a loose, hanging brown wire at the back of the engine bay on the right (as you look at the engine). It should be attached to the rocker cover rear right stud (10mm).

Failing that the voltage stabiliser at the rear of the clocks may be faulty but I'd bet 10p that the brown wire will resolve your issues. 

The Fuel and Temp and Tach I have seen can be caused by the 10V stabilizer or the Earth to the Clocks.

I had a set that the Tach was abut 400 RPM off, but the fuel leg and the Water temp was lower than expected, turned out that the Stabilizer was flaky.

I have a thread on adding a new Ground to the OEM in, that is straight to the frame behind the clocks, and the
easiest way to test your clocks is to test the 10V stabilizer in the car.  

Middle leg is ground so you can ohm that to the frame for 0 anything else is bad add a ground or you will have a bad mylar run and need to back feed it.

From the Middle leg of the 10V stabilizer to each leg one will be B+ or 12.5V( Key in and not running but in the first position.) on the other leg you would see 9.5 to 10V.