I have several problems with my Buick Regal. (1) Sometimes the seat automatic goes all the way forward when I turn the key on. (2) Sometimes the head lights goes out completely. I have to flash the high & low beam on to get them to come back on. I have to travel with the fog lights on in case the headlights goes out. (3)At times I can't get the ignition key out and I have to keep turning car on and off and move the shifter from park to drive then back to park. (4) As the weather start warming up, I always have cold air blowing out of vent. Have you heard of any of these problems?
seat problems; headlight problems; ignition key problems;air conditioning problems on 2003 Buick Regal
According to my service information you do not have memory seats so there is no control module controlling your seats. I would suspect that you have a wiring problem causing voltage to be supplied to the seat motor when you turn the key on, the problem would almost have to be in the seat or the switch. 2) You may have a problem with the high beam dimmer switch. I would suggest to check power in and out of the dimmer switch when the problem is occurring to confirm the fault. 3) There is a switch in your shifter that allows the key to be released when the shifter is in park. The most common cause for a sticking shifter is coffee or soda spilled into the shifter. If that is the case the shifter can be removed and washed under hot water to remove the residue. Lastly, make sure the cooling system is full of coolant and there is good flow through the heater hoses. If that is all OK I would suspect you have a heater temperature door actuator that is not working correctly.