Pontiac Grand Prix Forums : Grandprix

help me.. my heat only blows on the windshield.. is this the blower motor resistor??? or do I need something else aswell..... Thanks guys before hand..

probably your vacuum line to run your climate control, which runs across the firewall to the engine. If it becomes unhooked then it won't select anymore

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F clean cars, I Ride Dirty!.....to hide the wicked body damage...
97 GP GTP- Mystic Teal, 218k, fixing the damage
91 Cherokee- 4 in. Lift, 31 Kumho M/T, tons of fun
03 Chevy S10- full bag setup on order, will drag frame in under a month

whoah thanks for the quick reply yo.. so by any chance would you have some suggestive remedies?? can i fix this myself with my limited knowledge... or is this a biggie that only a pro can take on??

well can I HOOK this back up?

if that is indeed the problem, yes. it is as simple as that.

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2001 GT: cat/ubend/resonator delete, zzp PLOG, custom intake, DHP pcm

The default setting is defrost on the windshield. It is either a vacuum issue, or if you have electronic climate controls, the mode door actuator is bad.

To fix, you need a vacuum gauge and strat checking vacuum under the hood, the line running into the car and inside the car. Next check all the actuators, temp, mode and recirc.

If you have electronic climate controls, you need to replace the actuator, which is found in the dash board. Search the site for blend door, ot temp door, and a write up will come up.

I wish it were the resistor, but it is not, that is for the blower fan speeds only.

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1999 Grand Prix GT - Sedan - Black
1998 Corvette 6-speed - 2003 Pontiac Vibe

thanks guys.. so i guess imma start with checking to see if the vacuum thing is unhooked...

Anyone MIND letting me know or where I can find a write up on how to get to me vacuum line?/?/?

also i just replaced my water heater.. could I had accidentally unhooked it then??? if so is it near the water pump

thanks bros

The main vacuum line is behind the intake manifold, on top of the engine. It is also near where the large rubber brake booster hose comes out of, and goes to the master brake cylinder. It comes off of it, and then runs along the firewall until it gets to the passenger side. Then it bends and goes down near the battery. It is a hard black plastic line. If you start looking near the battery and work backwards, that might be easier for you. Or look along the fire wall for it and trace it both ways, to the battery and then to the engine. I do not know of a wrirte up to lead you to.

This line goes into the car, through the passenger side. If you remove the glove box, you will see it inside the car then.

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1999 Grand Prix GT - Sedan - Black
1998 Corvette 6-speed - 2003 Pontiac Vibe

If it has been broken inside the wiring harness you can route a new line by the automatic shifter passthrough like i did, bypassing the vacume reserve.

There is a vac line down by the passengers feet near the console its purple i believe. See if its unhooked from a nipple. IF thats all cool its a blend door actuator and not fun to replace. I've done the passengers side on my car.

I can get you instructions if needed.

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1999 Grand Prix GTP
http://www.fquick.com/rynoman03
http://www.cardomain.com/ride/2172058

I have kind of similar issues...the car heats as normal, and the fans work normally. I have the digital DCC on mine and my issue is that it will not blow warm air to the feet on either side. It will however switch from the defrost to the vents. I have no other issues but it will not switch down to the floor vents on either side...ideas? I would normally say blend door actuator, but if this is the case both of them would need replacement? And if this is true, wouldnt it not move at all? Any ideas anyone?

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98 GTP Coupe- 180* T-stat, GMPP Front Sway Bar, Dual Aeroforce Interceptor's, TDC FWI, TDC Taylor 10.4's, ZZP SS Plog, ZZP 3" SS catted DP, ZZP MPS W/3.4, AL104's gapped @.055, 3800Perf. PCM

u guys have been huge help.. I will try to see what I can get done... I will report back... AND THANKS FOR ALL THE COMMENTS AND HELP... this GP community is the BOMB!!!!

mine did the same thing a couple of months ago. Mine was that vaccum line like pitman said earlier. It has a coupler in it between the pass. shock tower and the firewall. Mine was just pulled apart.

yours did the same thing as mine or the same thing as the OP?

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98 GTP Coupe- 180* T-stat, GMPP Front Sway Bar, Dual Aeroforce Interceptor's, TDC FWI, TDC Taylor 10.4's, ZZP SS Plog, ZZP 3" SS catted DP, ZZP MPS W/3.4, AL104's gapped @.055, 3800Perf. PCM

I have the same problem, and it sucks when I have to drive it in the cold. Feet freeze and seems there is nothing I can do. I even replaced my DDC and that didn't help. For some reason I always thought the carpet got unhooks or something.

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98 Grand Prix GTP - Custom FWI, 104 autolites, 180* t-stat, TDR Fbody Break Kit

95 Eagle Talon ESI - 2Gb Conversion, lots of mods still slow.

same thing as yours

welll...,either a vacuum line came unhooked or broke, or you have two blend doors that are bad...from what I have gathered anyway.

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98 GTP Coupe- 180* T-stat, GMPP Front Sway Bar, Dual Aeroforce Interceptor's, TDC FWI, TDC Taylor 10.4's, ZZP SS Plog, ZZP 3" SS catted DP, ZZP MPS W/3.4, AL104's gapped @.055, 3800Perf. PCM