temp gauge acting weird?

[1993shoguy]

When the car is off and if I use anything power like seats, windows, lights, etc. The temp gauge rises and does the same when the car is running not as bad. But im not getting an actuall reading for my temp. What to look at and how hard to hook up external temp gauge? 93 atx

 

[sperold]

Search this forum for temperature gauge, and temperature sender. Some people have hooked up pipe tees to have an external temp gauge and the factory gauge, like in a gauge pod on the windshild pillar. People have done this tee thing for oil pressure as well. It uses very small diameter pipe and threads in where your temperature sensor sits now.
Start by looking for ground problems in that harness and consider a new temp sender.