I have a 96 cherokee classic. The temp gauge didn't work when I got it and the guy said its because the motor was from a 99. I just recently checked the block and found out its from a 97. What should I start looking at to see if I can get temp gauge to work?

 

Your original engine had a temp sensor on the back of the head, on the drivers side. 97+ engines only had 1 sensor located in the thermostat housing. When I put a 98 engine in my 92 I hooked up an aftermarket temp gauge and used the drain plug on the drivers side of the block. Renix temp sensor location. Others have used T fittings coming off the thermostat housing.

 

sthon is correct one on the thermostat and one on the rear of the block!!!