Problem with fan blower/vents

[Johnnystats]

Hey everyone - Have a question. When I put on the A/C - nothing comes out of the vents - only the floor area and the defroster area. No matter what button I press, it will not come out of the front vents. Any ideas what that could be? This is for a 91 GP. Thanks!

Edited August 26, 2012 by Johnnystats

[RobertISaar]

the vacuum line that goes from the vacuum resivoir underhood to the vacuum distribution block for the HVAC stuff would be my first guess. no vacuum there means the vents are stuck in whatever direction they were in when they lost vacuum.

[Schurkey]

The usual cause on my '92 and 93 Luminas has been broken/worn-thru vacuum hose under the battery, leading to the round vacuum reservoir in front of the left front wheel. Have had to repair both of them there. Hard plastic vacuum hose splits, has to be "spliced" with a short section of rubber hose.

 

This kills vacuum to the HVAC system, leading to most of the air coming out the defroster with some coming out at floor level. The defroster is the default air door position as it allows for defrosting the windshield in cold weather--a safety feature.

[Johnnystats]

Thanks to both of you. Let me ask - I am not that mechanically inclined - so would this be a hard/costly thing to get done?

[RobertISaar]

vacuum line is SUPER cheap.... it's finding the bad spot and getting to it that takes some thought/time.

[Johnnystats]

Just to give you an update - they were able to trace the leak rather quickly and make the repairs. Thanks again for everyone that responded!