mmorin1

My climate controls work only on setting 5 and only when blowing through the defroster. I think it may be a vacuum line issue, the only problem being I cannot find the vacuum lines under the hood. If anybody could tell me where to find a diagram of them online or suggest/know what the problem is (if my theory is incorrect), please let me know. The car is not supercharged and has a 3.8 engine.

grandprixgtx00

is it ONLYwhen you have it on the defroster that the #5 speed works? because a common problem on these cars is the blower motor resistor, and that may be your problem

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as of Jan. 2009:

'97 Grand Prix sleeper SE (132K)
'98 Grand Prix GT coupe (79K)
'00 Grand Prix GTX coupe (32K)
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mmorin1

Yep. Settings 1-4 I get absolutely nothing. And when I switch it to another setting besides defrost, it is still blowing, but nothing is coming out.

tech657

If your blower works only on 5 then the resistors are bad. It is located under the dash on the pasenger side next to the blower motor. If your controls don't work, it is the control unit. I had the problem where my controls would just blow cool air. I thought it was a vacuum leak but it turned out it was internal and you need to replace the controls. Unit is about $200.00 but worth it to have Cold A/C in Summer and Hot air in winter.

brcidd

The vacum line runs down by the battery to the vacuum reservoir in front of driver's side front wheel-- the line cracks and breaks due to battery acid venting onto it-- this is a very common problem on W-cars- I've fixed dozens of them this way by using a piece of rubber hose to splice it- this will get you the proper air delivery inside- the blower resistor needs replaced to get lower fans speeds

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Automotive A/C Engineer with:

'95 Chev 3500, 454 Dually Crew Cab- 145k miles- Wife's Camel trailer puller.
'94 Astro- 370k miles
'94 Firebird Formula- 5.7L 180k miles- gone- blown head gasket
'92 Chevy Lumina Van 3.8L 264k miles
'86 GMC S-15 - 2.8L 154k miles
'86 Buick Park Ave 3.8L 199k miles- my daily driver
'77 Chevy Vega- 2.5L 175k miles gone but not forgotten
'68 Camaro 396 4 spd RS/SS -72k miles- my high school car!!

All but the Camaro and Firebird are white....

steveocray

My car would barly switch betewwn vents, yep found a check valve that supplies vacuume near the battery as you described badly acid dammaged.
THANKS !