91 s10 4.3, dash analog gauges not working properly

[wrye]

Oil pressure reads about 70-75 psi always, Volt meter reads about 15+ unless AC or ? draws it down, Temperature reads 140-160 after warm-up and climbs a bit under load. Engine is not that hot, oil pressure in not that high and voltage reading at the battery is normal.
The gas gauge seems to work OK but does stay on over-full a long time. Speedometer works OK.
The ground connector above the steering column with 6 spade terminals has only one double black wire connected to it and it appears to originate from the cluster. All are tight and clean.
I've been chasing ground connections but need some guidance.
Any advice would be appreciated.

 

[DerekTheGreat]

Try a different, known good instrument cluster from another S10 and see if that nets any differences. Another place to start would be to measure the inputs coming into the cluster. Although I don't know what the ranges are. There's gotta be a spec out there somewhere. I imagine you can also test the cluster too, like a particular gauge should read a specified value given a specific voltage..