Spark plugs and wires - good
O2 Sensor....Bosch OEM replacement
T-stat...I noticed that its been holding temperature pretty good...when it reaches right below the 210 mark, the temp will drop to about 180-ish, then so on, so I ASSUME this is the thermo working as it should.

 

Where is it???

 

The AUX fan sensor is on the radiator on the drivers side. However the mechanical fan if working right should pull plenty of air to keep the jeep cool, especially in the winter months. Even during Summer when the temps outside reached 110, my AUX fan only kicks on with the A/C and if i'm idling for a long time. I am thinking something else in the cooling system is not right, like the radiator or the water pump. Old jeeps are notorious for the radiator cracking and causing grief. When mine cracked it didn't leak any antifreeze, it was just big enough so the cooling system couldn't pressurize thus causing the engine to overheat. Make sure all the heater hoses are tight, and not leaking. The renix cooling system is poorly designed, and if there is any leaks in the cooling system not allowing it to pressurize, it simply just doesn't like to work. My cooling system started acting up again during the summer, and the cooling bottle itself was cracked (i have gone through 3 of them)... so i replaced that and the cap and i was good to go. Just my 2 cents.... its not worth much, but there ya go anyway haha.