2002 Grand Caravan air/heat system fan control

The fan control in my van has taken on a mind of its own. I can no longer control fan speed. It seems like it is stuck on high (can’t adjust lower or higher). Whenever I turn the system off, the fan only seems to run faster. What could be causing this to happen?

perhaps you need a new fan control switch.

Is there a separate rear control switch? Does this van have a switch on the dash to give the rear switch the control?

I think the solid state speed control module has shorted. Being shorted it allows power to run the blower motor continuously. If it is the controller you may be able to replace it yourself. It will be connected to the blower motor. The module replaces the resistors that most systems use and it allows a variable adjustment of the speed instead of just a few speeds.