Have a 99 grand Cherokee 4.0l temp gauge going crazy. I change the sensor, thermostat, flush the radiator, disconnected the battery for 10 min or more, been checking for ground short, disconnected the PCM and still doing the same thing. I unplug the sensor and the gauge still going crazy that's why I was checking for a short. Plz help

 

ok it's going crazy... does the engine run hot? Did you check to see if the problem is actually your gauge itself? When you installed the new temp sensor did you put any kind of sealant on the threads because they are supposed to self seal and ground through the threads to the block.

 

if you unlpug the temp sensor at t stat housing your temp gauge should not read any temp

 

thanks for the reminder... COMPLETELY forgot about this quick test too.

 

Ok o got it! It was the wires touching inside the plug of the PCM. I took that cover off and the wires were stock together. Thank you everybody for all the advises!

 

hey that was easy