Got a 89 f-150 with the 302 temp gauge doesnt work.
Is it just the gauge or could it be something else?

 

Your ECT sesnor by the thermostat is most likely bad. Could be the wiring. I don't think I've ever seen the gauge on the dash go bad.

 

If you want to test the sensor, you could warm up some water and test the voltage, but they're pretty cheap. I would just throw another one in there.

 

Unhook the sender wire, the gauge will go one way. Ground the wire, the gauge will go the other way.

 

Alright thanks for the info

 

I just replaced the sensor and the gauge still doesnt work.

 

Did you try what I said?

 

You need to test or replace the temperature switch not the temp sensor by the thermostat. The sensor sends info to the ecm the switch works the gauge

 

I'll go ahead and say what many others were probably thinking. I'm an idiot. The one that controls the gauge is in the block. The one in the block will be a more stable reading while the one at the thermostat fluctuates to give the computer a good reading. Bone head moment.

 

Where are these wires you talk about? And where is this temp switch at?