I own a 96 XJ that I was driving the other day and heard the coolant boiling into the overflow. My Temp light never came on. So what I did was replace the sending unit and the coolant temp. senser because the light nor the electrical fan kicked on. I then filled the radiator and resivor. now whats happening is the light stays out even when i start the jeep it never comes on for thos few secs. its supose to. And even when i over look that and keep the jeep running or take it around the block, pop the hood and the fan still doesnt kick on but the top radiator hose is hot. I hard wired the fan to batt. and it works. checked the rely and it works. The best is if i unplug the conn. to the coolant temp senser the fan will kick on but never shut off. i had a few people look at this monster of a mess and i got nowhere.