Instrument Panel, Gauges

I recently got a 1992 gmc sonoma but the oil pressure gauge allways stays at the highest level (80psi) no matter wheter the truck is on or off and also the temp. gauge doesnt work either it allways reads 0 even after been running all day long. my battery gauge works fine any help on this is greatly apprecatied . thanks very much.

The sending units might need to be replaced...which motor?

its a 2.5