Temp gauge

[Chris350]

Hey everyone, new to the forum. I recently purchased my second 86 c10. The temp gauge isn’t working properly. It pegs all the way cold, then all the way past hot with no rhyme or reason for it. Either way it’s not accurate. Short of checking continuity in the wire, any other things you have found while diagnosing these before I dive into it?

 

[PrairieDrifter]

Temp sending unit. Make sure you get the correct year range for your gauge cluster, they all have the same threads.

 

[Matt69olds]

Before investing too much time checking other things, throughly inspect the wiring. If the needle is swinging wildly from one extreme to the orher, you may have a wire occasionally ground out (causing the gauge to read full hot) while the wire to the gauge is open (meaning it will read cold when the wire isn’t grounded). You may have 2 problems causing the same concern.