Hello, i have an XJ8 and the cooling fan will not turn off! the engine is off, and cold, and it still will not turn off. the only way it will turn off is obviously disconnecting the fan plug itself. please get back to me asap!!

 

Probably stuck relay.

 

I'd guess the fan relay has stuck on as well. Swap it with another relay such as the A/C relay.

 

Zbabar,

What year is your XJ8? I want to look it up on a wiring diagram. I'm not sure your car has a relay for the fan. If it's the system I'm thinking about, it's a fan/module assembly. I think it's 4 wires. Ignition power, battery power, ground and a signal from the engine control module.

If it's like I think it is, it's most likely a bad fan/module asssembly. It may be a pulse width modulated signal to a variable speed fan/module assembly. It's possible that the fan module is not seeing any signal and is going into fail-safe and going to full speed on. You need to verify the signal, power ( batt and ignition), and ground. If it's all there, my money is on the fan/module assembly.

I'd like to verify the year and wiring first.