My old radiator went out on me during a drive and my engine overheated. I replaced the old radiator with a new one but since ive installed it the fan doesnt turn off unless i turn off the car.

It will kick on as soon as i turn the key, even without the engine being on, and stays on. So as long as power is on, the fan is on. The temp gauge is also stuck since overheating.

Could this be a fried sensor causing the fan to come on or a bad relay switch?
1989 RS 5.0L 305 engine

Thanks!

 

The cooling fan switch is located in the pass. side head in between the #6 and #8 spark plugs.

If you unplug it and the fan keeps going, relay's bad. If you unplug it and fan shuts off, fan switch is bad.

Temp gauge needle may be stuck in the bezel (requiring you to disassemble the bezel to move needle) or temp sending unit went bad. Does the needle move at all under any conditions?