I had a vac leak at lower intake manifold. Garage fixed this and when car was return and I started it I notices that the interior temp on the climate control was flashing. I have never had a problem with the climate control. Garage that repaired the vac leak couldn't find a problem and said I'd have to take it to Pontiac. The problem that it has is that the climate control won't regulate the temperature now. Everything else works. Fan will slow, air will eventually move to the dash vents ect . . . but the temp coming out is ALWAYS HOT! Even if I drop the temp to 60 and turn on the AC, it still puts out hot air. Does anyone have any ideas on this? What caused it or how to repair it?
Thanks
Rod

Probably what caused the problem, when the battery was disconnected the Auto Climate Control (ACC) was not turned off first. If the ACC is active and you disconnect power, it would have the same effect as pulling the power supply plug on your home computer, it will lose unsaved memory. The flashing light indicates that a fault is stored, and that is obvious from what you have described. If the temp remains HOT in all settings, this would indicate the blend door actuator is not moving the blend door for some reason. You would have to remove the glove box to get a view of the operation of the blend door actuator & rod. If this is beyond your mechanical talent, it may require professional diagnostics.
http://img169.imageshack.us/img169/8486/heaterboxmn1.jpg

Thank for the information! I'm curious at to the battery being disconneced though. I have a security code set for the radio and when the car was returned, I didn't have to enter the code in order to get the radio to work again. I either they (mechanics) have another way to avoid this or they didn't disconnect the battery, which isn't good either!
Anyway thank you very much for the response!!!!
Rod

Noticed that after you drive the car when it is NOT putting out any heat, if the car sat for a little while and then you start it, it would then put out heat. So lately, when it won't put out heat as I drive, I'll wait for it to warm up as I drive, then put the car into neutral and shut it off, restart right away and back into drive. Then I get heat! What is going on? A sensor maybe?

Noticed that after you drive the car when it is NOT putting out any heat, if the car sat for a little while and then you start it, it would then put out heat. So lately, when it won't put out heat as I drive, I'll wait for it to warm up as I drive, then put the car into neutral and shut it off, restart right away and back into drive. Then I get heat! What is going on? A sensor maybe? Have you checked your coolant level? This could be air trapped in the system and you need to follow the bleed procedure using the vent on the thermostat housing. First, remove the cap from the radiator when it is cool and see where the level is. In addition, be sure the overflow tank is at the correct (cold) level. BTW, do you still have the flashing light?