Temperature gauge

[Chris350]

I need some help on this one. I bought a 1986 c10 305/th350 Silverado 6 months ago. The temp gauge goes cold to overheat randomly, nothing in the middle. I did the easy thing first and swapped sensor. Same thing. Today I swapped the printed circuit and gauge while it was out. I have the same problem. Any one else have this issue before?

 

[85K304SPD]

Body ground from engine to the firewall?

 

[BurbanPena]

your wire for the temp sensor may be frayed or the wire casing rubbed off on something you can run a new wire from the fire wall down to the temp sensor and see if that fixes your issue

 

[Big red square]

Mine is stuck on cold.
Any suggestions?