Ac/heater doesn't turn off on a 2004 Pontiac grand prix

SOURCE: grand prix 3800 blowing only hot air please help

check the temp control switch in the dash

SOURCE: LOOKING FOR A FUSE BOX DIAGRAM FOR 2004 PONTIAC GRAND PRIX GT

It's under the hood, on the driver's side, under a square, black box with a lightning symbol on it. Loosen the flower-shaped screw that holds the lid of the box down, remove the lid, flip it upside down and when you look at the inside of the lid, you'll see a map of all your car's fuses. There's also a fuse diagram on the very end of the dash, but it's accessible only when you open the driver's side door. When you're driving, that end of the dash is blocked by the closed door.

SOURCE: my 2004 pontiac grand prix window it will go down

Does it try to come up, EG is there power being applied when you press the UP switch? if it makes no sound or movement when pressing the UP switch it is probably a worn out switch - available at Pontiac dealers though you may have to order it and wait a few days - have your VIN number for the parts desk and you'll get the part in no time - the switch levers out of the panel - use a plastic tool if possible to prize the switch out so you don't damage the surrounding trim - the cable connector clips off the old switch and goes on the new switch, press the switch home into the recess and jiggle it a bit to make it dead flat - window should work now.
If it IS making an effort to come up then either you have a poor earth or power connection making it so there is not enough power to pull the windows up (which is harder than down due to the weight of the window) -- check the cabling behind the door panel, and as above pull out the switch and check its connector too.
OR... the window is out of alignment and is jamming - putting it back in alignment means taking off the door panel and getting at the bottom of the window runner, loosening the bolt(s) on the bottom of the runner and moving it sideways so it hold the window steady but not tightly, you may have to try having it tighter or looser against the window till you get the best performance - also oil the moving parts/cables of the window mechanism (dont get oil on the glass, it will smear for weeks) to give the best chance of smooth operation.

SOURCE: Car Heater Not Working - Blowing Cold Air

also check to see if tube that runs your climate door is not pinched or broken. the vaccum tube that runs the climate door is behind and under the battery. i had same problem a year ago and the tube was partially cut. i fixed it by cuttinga piece of aquarium tubing and spliced it back together. one other thing.....check to see if your radiator over flow cap is tight. your cap maybe bad and or cracked this would also cause the problem.

SOURCE: 2004 Pontiac Grand Prix GTP front pass turn signal doesn't work

you would need to buy a blinker relay