Temperature Gauge out of calibration - GTI

After months of swapping sensors and thinking there must be an electrical issue with the wiring I swapped the cluster with a spare GTI one.
Mine is in good nick, everything works (inc MFA) but the temp needle climes to full scale instead of settling between 1/2 and 3/4.  On Saturday I swapped the cluster and the other one and it works perfectly.
So now can mine be repaired/recallibrated  or should i just swap the gauges?
Or could it be a dodgy resistor on the top of the cluster?

   

Most all issues that I ever had with the cluster is that the Gauge itself had bad solder connections, or the 10V stabilizer was bad.

If your Fuel gauge is working correctly then the stabilizer may be good and you are having a gauge issue with the water temp gauge.

If your cluster has a good ground, and 12V to the cluster on it, then use the test from the Bentley to measure the voltage on the stabilizer.  On the Center pin there is ground, on another there is Battery voltage, and the 3rd leg has 10V.  

I have a few how-to's in the archive section on flaky temp gauges, and things.

I have never had a gauge that would read high it was always intermittent either worked or it didn't.  The issues with my 3 cabbies, had always been cold solder joints on the nutted pins on the rear.  Since there is a small logic circuit inside then your gauge could be bad.

Thanks,
Great advice.  Suspecting a voltage regulator problem I cleaned and changed the units from cluster to cluster, but this made no difference.
I also dismantled and cleaned the two "nutted"pins on the rear, but again no change.
So it must be in the gauge either a bad component or a high resistance joint " maybe try the Oly' s repair (on YouTube)