HELP A/C Fan Not working correctly HELP

[97stomper]

I have a similar problem with my electric fan in my 97 not coming on at approx 218 deg and above. It has come on with the A/C turned on (however, I didn't run it long and don't remember the engine temp at the time). Last night I hooked my scanner up to the jeep and watched the live data until the temp reached 226...no fan. The gauge is accurate at 210..but doesn't even make it to the next line up for 226, which I find confusing based on the markings and the differential between 210 and the top 260...but that's another topic.

The fan came on and continued to run when I pulled the temp sensor connector, but I didn't have the jeep up to full operating temp at that time either.

Tonight I will try and check the temp sensor disconnect when the engine is hot. Could my fan problem be heat related?

I wouldn't think it is the PCM if it comes on for the A/C and when the ECT sensor is unplugged.

Thanks for your help,

Rob

 

[kastein]

Yeah, if it comes on when you unplug the CTS/ECT sensor, you can rule out anything except the sensor itself and the temperature of the coolant. Doing that proves that the sensor wiring, ECU, relay wiring, relay, fan, and fuses are all functional.