my 96 4.0 cherokee running 217-220 idling and driving down road. new t-stat ,new water pump, new temp sensors, new cap , new fan relay and new fan clutch. The aux fan wouldn't run unless i unplug the temp sensor in the front on the t-stat. i really need help here.

 

Do you have a fan shroud? Also my aux fan only comes on with A/C or unplugging the temp sensor. I tested everything and my ECM is not turning the fan on, am gonna wire it on myself here shortly. What temp t-stat did you get?

 

How old is rad? Efan comes on at 218. Verify coolant temp with a point-n-shoot infrared temp gun pointed at the t-stat cover.

 

or o2 sensor is bad, making it run rich.

 

the fan shround is on it and the fan doesn't come on when i turn on the a/c

 

o2 senors one is a year old the other is brand new
but check engine is on

 

how accurate are the stock temp gauage it is 15 years old

 

That's why I suggested verifying temp. How can u tell 217-220 by the factory gauge?

 

Ok, the relay is on the passenger side of the engine compartment. Check fro power at pin 30 first, if you have power use a paper clip and jump pin 30 to 87, see if the fan comes on. If it does you have a control side problem or a bad relay. If it does not you may have a bad fan.