Temperature gauge and gas gauge issues?

[Augusta]

Okay I know there are a lot of posts about this and i have read many but still could use some suggestions.
My 72 Jimmy had an issue with the temp gauge not working as in the needle was all pegged all the way cold and wouldn't move even when grounded at the sending unit. So I replaced sending unit, nothing changed. Took out the dash swapped in another temp gauge no change, at this time i noticed my gas gauge wire was a little frayed where it came through the firewall. So i fixed that and put everything back together, Now both gas gauge and temp gauge are pegged hot and don't move. IDK whats going on? Thanks

[Palf70Step]

Normally when the gas gauge pegs like tht it took a power zap and ruined the gauge. I suspect you got voltage into the grounding circuit and it popped the gauges. before replacing check you voltage and grounds

[Augusta]

Yea I don't think that happened. I have another cluster and they are doing the same thing on that one. I'll keep looking, always something!

[pjmoreland]

If your fuel gauge is pointing way to the right past full, this is usually an indicator of a poor connection to the sending unit or a problem with the sending unit. Try touching the tan fuel sending unit wire to ground and see if the gauge moves to Empty. If it does, then this indicates an issue with the fuel sender.

Have you tested the resistor on the back of your temperature gauge? It is responsible for pulling the gauge toward Cold. The resistance should measure at 85 Ohms and must be measured with the resistor removed from the gauge.

Was your truck originally outfitted with a gauge cluster that had a temperature gauge?

[leftybass209]

You should check for continuity on the temp sending wire. How does everything else function? Lights work okay? Any damage to the circuit board traces?

Was this truck born a gauge cluster truck or has it been swapped from a dummy light cluster? Have the gauges ever worked since you owned it?