[Vwdiesel] VW instrument cluster problem

[Caleb Van Dyke]

I have a 1981 Rabbit pick-up with the diesel, and I am having a strange problem with my temperature and gas gauges. Every so often, the temperature reads about 3 notches higher, as well as the gas gauge. Then, for no apparent reason, goes back to where it was. This has me wondering if there is a loose connection somewhere, a voltage imbalance or surge, or ???
I have noticed in my Haynes manual that in 1982 VW put some sort of a voltage controller in their dashes. I do not see this on my dash set-up, so I'm assuming it wasn't avaiable in '81.

Thanks for any help.

Caleb