Saturn stalling problem

Ok ? I have a totally weird car problem. My 1997 Saturn SW2 started stalling this last weekend any time 1) the brake lights came on, 2) the backup lights were one (i.e. anytime you shifted into reverse), 3) the rear-window defroster was turned on or 4) the running lights were turned on ? it wouldn’t stay running long enough to get to the headlights. The puzzling thing is that it would start up just fine after each stall, the radio would continue to play, the safety lights in the front were on, and it ran fine. I could run the vent fan all the way up, and it kept running. I checked the battery voltage (12.4V) and the voltage when the engine was running (14.5V), so I think the alternator is working properly, and the battery has enough juice to re-start the car each time. My mechanic is baffled, and so am I. Has anyone seen this problem? Any ideas? The battery is about 2 years old, and the contacts on both (+) and ground are clean with no sign of corrosion. Help!

-----Wade Hutchison,

When electrical, air conditioning, or other load on the engine increases the motor is supposed to slightly speed up to handle the increased load. The throttle position sensor might be failing. It could be the sensor that detects the heavier electrical load is bad. Or it might be some massive short in the multifunction switch in the steering column or some other circuit that stalls the car, but you or your mechanic probably would have tracked that down.

Turns out it was the ignition module. Replaced that, and all is well.