1990 Oldsmobile question

The A/C works and as far as I know the heat works(don't use heat much here). Anyway it's an 1990 Oldsmobile Regency. The blower-motor will start running sometime after the car has stopped(turned off). Just got this car and don't know much at all about cars in general. As soon as I put the key in to start it, don't even have to turn it, the motor will stop. Once started everything starts running like it should. My brother was saying that it could be something too cool down the car. But after telling him that the air is coming from the defrost area just below the front windshield he said that it's probably some kind of problem with the blower-motor. Right now just don't want something like this running down my battery making another problem.
Just wanted to post here and see if anyone else has had this problem and knows what it's about or how to fix.

Thx

If your car is equipped with the c68 electronic climate control system (its printed on the front of the control head, if in doubt, check the "SPID" label in the trunk on spare tire cover for option code C68) anyway, this is the model with automatic blower control speed, based on various inputs. If the blower contines to run with the key out of the ignition etc.. you need a new blower control module, GM part number 12484912, list is $158.61, but you should be able to get it for less than list. It's located under the hood, center rear of the engine compartment in the HVAC case. You have to remove the black plastic cover on the cowl to see it/remove it. It has 4 wires going to it. A large red one that's hot all the time, and a gry/blk wire, purple wire, and a black wire. 4 screws hold this unit in the case. Pull it strait up, (it has aluminum fins on it) be careful pulling it out, as the bottom of it is right next to the A/C Evaporator core, you don't want to puncture the evap core. Yes it will run down your battery if left to run continuously. If I misunderstood your condition, just repost and I'll try to help. Your car may have had an "Afterblow module" added to it to prevent mold/mildew growth in the HVAC system. Hope this info helps.

Thanks for the info