I have a 1980 pickup (with a 83 22r swap) and the water temp, fuel level, amp meter and oil pressure gauges are not working also the lights/headlamps flicker with rpm at idle but the tach works "go figure".
Now someone made a mess of the wiring in this poor pickup and i cant't seem to make too much of the home grown wiring and such, I suspect grounds but haven't been able to locate all of them all as well as the temp sensor auto zone sold me i for a 83.

What i have replaced:
temp sensor
thermostat

What I have tested:
temp sender/sensor resistance
temp gauge resistance (both where good according to the FSM)
engine temp is good at around 80/85
amps are showing 14.5 +

Please assume i am retarded since i no very little of wiring
Any help would be greatly appreciated !

 

I tested the resistance at the temp gauge and is showed 25 from pin to pin and 550 from ground to pin when engine was warm witch is the same as i got from the sensor to the ground.
The oil pressure gauge started working after i installed four ground wires(rear of head, ac bracket,intake manifold and under power steering bracket) no luck on the fuel or temp.

 

It sure looks like you have a temp sensor instead of a temperature sending unit at least from the picture .

You have the correct sending units for the cluster you have ??

Some times a year can make a difference in what signal the gauge looks for.

 

Thank you that was the case, i can rule that out.