Just replaced the PCM in my 95 GC, and it is running like new. However, I noticed my temp gauge stopped working. I replaced both sensors and have good resistance so the sensors are ok. I just put new grounds in so that should be good. Is it likely the gauge has gone bad or the positive connection under the dash is bad?

 

Okay it's possible this is old enough to have an actual analog electrical gauge. These work on a "shunt" system where the coil that powers the needle, a set value resistor, and the temp sensor are connected in a delta circuit. Basically on the back of the gauge there should be 3 terminals. One is 12v power, one is the sensor connection, and the third has a resistor connected to it that is also connected to the power terminal. The resistor looks like just a metal bar.

My 67 Camaro had this type of gauge and it also quit working. All I did was disconnect all three terminals, clean the areas when the nuts held the wires, and put it back together. Bingo! It worked! The resistor was a bit loose and that's all it took to not function. The fuel gauge works the same way. Any difference in voltage between the sensor and the set value resistor changes the needles position.

I hope this helps.

 

Thanks, I think I’ve discovered the cause and affect. I had the dash pulled apart and when I pounded in the snap in pins over the gauge console, I think I may have damaged the temp gauge.