Bought jeep this spring has been running fine no issues. Temp seems to run around 190-200 range. Turned AC on, after a bit noticed temp had climbed into the red. I shut off AC and turned heater on temp went down to 210. I pulled over and looked under hood noticed only fan on passenger side was running, I assume both should have been running at this temp ,would that be correct. Coolant is at correct level.

 

Yes both should be running, the efan connecter is located right on top, hot wire it to the battery and see if it's running. If it runs then you need to change your temp sensor. The efan connecter has a tendency to come loose in my experience so it may be just that the lock tab (the red thing) has come loose (two stage lock on that connector) and the efan isn't engaging.

 

If a/c is off and coolant temp is below 218 (say 210), efan will be off. How old is the fan clutch?.....what cooling system maintenance has been done?