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1997 Eldorado
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637 Posts
Discussion Starter #1
ok well my fixed my ac and its working good but i noticed when i accelerate the ac blower slows down to no air out the vents. once i let off the pedal it blows fine. i was thinking its a vacuum leak somewhere but where? anyone have an idea or had this issue before and know where the vacuum leak could be? or could it be another issue?
 

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Super Moderator
2010 DTS
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87,543 Posts
That would not affect the blower, but it does affect the mode doors on the '97. I'd suspect that the air is being diverted to the defrost vent as it is the default mode. Most common leak point is the parking brake release diaphragm. If the brake does not release when the car is put in gear, there is the leak. If it does, then you have to pull the cabin vacuum supply at the firewall on the passenger side. If you have vacuum there, then the leak is in the cabin. If not, then it is under the hood. Start tracing the line back.
 

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1997 Eldorado
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637 Posts
Discussion Starter #3
That would not affect the blower, but it does affect the mode doors on the '97. I'd suspect that the air is being diverted to the defrost vent as it is the default mode. Most common leak point is the parking brake release diaphragm. If the brake does not release when the car is put in gear, there is the leak. If it does, then you have to pull the cabin vacuum supply at the firewall on the passenger side. If you have vacuum there, then the leak is in the cabin. If not, then it is under the hood. Start tracing the line back.
hit the nail on the head ranger. ac is comming out the front defrost vent, and the parking break is always sticking i have to use the manual relase anytime i use it. so how can i fix this issue?
 

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2010 DTS
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Start by having an assistant put the car in gear while holding their foot on the brake. You pull the vacuum hose off of the parking brake release diaphragm and see if you have vacuum. If you do, then the diaphragm is leaking and needs to be replaced. In the mean time, just plug the vacuum line with a piece of tape or a screw.
 

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1997 Eldorado
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637 Posts
Discussion Starter #5
Start by having an assistant put the car in gear while holding their foot on the brake. You pull the vacuum hose off of the parking brake release diaphragm and see if you have vacuum. If you do, then the diaphragm is leaking and needs to be replaced. In the mean time, just plug the vacuum line with a piece of tape or a screw.
will do thanks alot ranger :cool2:
 

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1997 SLS
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550 Posts
I've had this leak before too and there's an easy place to start your search. There is a vacuum reservoir just under the passenger's side fender (up front just under the battery). Look up under there for a large bullet shaped plastic thing with a line coming out of it. It's a short line that gets battery drippings and road debris on it causing it to fail. The other side of the line goes into a plastic line that usually is safe from battery acid. Mine goes out every few years so it's PM for me. Most automotive places can sell you a foot or so cheaply - just bring the old line in.
 

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1999 White Diamond STS with Sirius, 2001 Silverado
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440 Posts
Not to hijack the thread, but my parkign brake sticks a little, I usually have to shift out of park twice to get it to release, or jiggle the pedal. I jsut thought the pedal was getting caught on something. I'll do Ranger's vacuum test today and see whats happening.
 

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2010 DTS
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Not to hijack the thread, but my parkign brake sticks a little, I usually have to shift out of park twice to get it to release, or jiggle the pedal. I jsut thought the pedal was getting caught on something. I'll do Ranger's vacuum test today and see whats happening.
Vacuum is not your problem if it is releasing. You need to lube it or a cable may be getting rusty.
 
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