You'll need to clarify the symptoms.
"fan motor operates on high, cannot adjust speed but can change temp and air flow direction. This happens with the HVAC controls turned off."
Nothing should be working if the controls are turned off. Do you mean the air conditioning is turned off but the heater is turned on?
'96 and '97 minivans needed to have a relearn procedure done anytime the battery was disconnected or run dead. Half of the procedure can be very frustrating and time consuming to pass. By 2000, the procedure was either simplified or it wasn't required, I can't remember; and, I don't think that applies to your 2003. Nevertheless, I would check the service manual, (sorry, I don't have one), for a calibration procedure. If there is none, I'd suspect the HVAC computer.
This is the main reason I'm still driving my '88 Grand Caravan; no over-complicated unreliable computers, and my heater works just fine. "Thanks, car manufacturers"!
Sunday, March 22nd, 2009 AT 5:46 PM