AC blowing thru defrost vents - AC Auto Repair Help Forum


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AC blowing thru defrost vents

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Auto Repair Home>> Automotive Repair>> AC Auto Repair Help Forum

brianr35
New User

Jul 17, 2008, 11:38 AM

Post #1 of 4 (2533 views)

AC blowing thru defrost vents	Sign In

2003 Jeep Cherokee, 79,000 miles.
My AC is blowing cool air, but it is coming out of the defrost vents. It eventually filters thru the regular vents, but only periodicaly. This has happened before, and my mechanic said a hose was loose. I would rather try to tighten the hose myself or replace it if possible, but I do not know alot about cars. Any help would be appreciated. Thanks

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 17, 2008, 12:29 PM

Post #2 of 4 (2525 views)

Re: AC blowing thru defrost vents	Sign In

I believe this actuator door is vacuum operated and YES a vacuum leak in a hose would cause this. The ductwork default in most vehicles is defrost.

Look for vacuum hoses underhood that are cracked, broken etc. Chances are it's on passenger's side somewhere underhood. Some vac lines look like wires and can be patched with like windsheild washer hose over bad/broken area.

Pretty much only one vacuum line goes in thru firewall so trace back from that if you can't locate which.

If a hose isn't staying on tight, try cutting off 1/4 inch for better hose if there's enough. These generally don't use clamps,

T

gef4132
New User

Aug 15, 2008, 9:22 AM

Post #3 of 4 (2436 views)

Re: AC blowing thru defrost vents	Sign In

1994 gmc jimmy air blowing thru defrost vent but not thru main vent . please send some help

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 15, 2008, 9:46 AM

Post #4 of 4 (2434 views)

Re: AC blowing thru defrost vents 94 GMC Jimmy	Sign In

I think this vehicle uses electric actuators to direct air to desired ports. Default position is thru defrost ducts in most all vehicles.

Look for vacuum leaks, hose disconnected anyway underhood usually if vacuum controlled. If electric it would be the controls aren't telling the actuators what to do OR - acuators stuck, door stuck, rods that move the doors broken or disconnected.

Not certain but GMs probably put that actuator motor if electric on driver's side of airbox over the gas pedal area,

T

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