Phantom A/C or Heater Fan

I have a 1995 explorer. Recently, I find the cabin A/C fan staying on after the car is turned off. This is not the radiator fan, it’s the one inside the car. I have to disconnect the battery to make it quit. Could this be a bad relay? The A/C and heater work fine when the car is running.

It’s most likely to be the electronic speed control if you have auto or semi-auto climate control.

It does have the auto climate control. Can you just replace the fan speed controller, or do you have to replace the entire panel?

The fan speed controller is a separate module (it’s just a transistor, relay, and a few other components). You will find it in the air stream near the blower. I don’t know if you get to yours under the hood at the firewall or under the dash. Either way, it will be on the passenger side. There’s no need to replace the climate control module (“panel”).
You can get the speed control pretty cheaply from a junk yard.