Heater/ A/C will only blow out defrost?

Hey there
As it says no matter which vent i turn the nob for it only blows out defrost. Doesnt matter heat or air so therefore since the compressor kicks in with the defrost the darn thing is always running. Ive looked and dont see any vacumn lines off im wondering if it could be the actual panel with the nobs but that doesnt look like it would be very intricate. Heck any one have any clues. Im clueless. Thanks

01 Cherokee

my experience with my '91 was the vacumm line wasn't connected. there are 2 main places to look. the first is the line directly to the vacumm canister (on the older models it is mounted in the front bumper), it may have a crack or isn't on tight,or the canister is bad. the second is the "one way disc valve" that comes from the intake manifold. if it is in backwards, it won't allow the vacumm canister to have any vacumm. on my 91 it is vacumm that controls all the valves. i believe that it defaults to defrost since at least the winsheild would be clear in case of a failure.

Just to get it out of the way, you should have used the search function of this forum. Anyway... my '99 suffered from the same problem (cruise control also didn't work) but I found out that the vacuum hose that runs beside the battery had been eaten away by battery acid, so I'd check there first.

Dmanti said:

Just to get it out of the way, you should have used the search function of this forum. Anyway... my '99 suffered from the same problem (cruise control also didn't work) but I found out that the vacuum hose that runs beside the battery had been eaten away by battery acid, so I'd check there first.

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Why do people like you always give people garbage about the search option? If someone cant find the info they need they ask for help, If you dont like it dont answer. This is a place for questions to be answered not for people to gripe about not doing enough research. Dork.

As far as the defrost goes I am glad you asked the question because mine has the same problem I just havent gotten around to figuring out the problem yet.

GermanXJ said:

Why do people like you always give people garbage about the search option? If someone cant find the info they need they ask for help, If you dont like it dont answer. This is a place for questions to be answered not for people to gripe about not doing enough research. Dork.

As far as the defrost goes I am glad you asked the question because mine has the same problem I just havent gotten around to figuring out the problem yet.

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Let's see now: "You should have used the search function first!" contains 8 words.

"It's a vacuum leak!" contains 4, or 5 if you count the contraction as two.

If the compressor stays running, you have a switch problem. A vacuum leak will keep the mode doors from working, but the rotary switch will still turn the compressor off and on.

Dmanti- thanks for the help that was it and i already fixed it. the line was under the batt. box so i never saw it.

GermanXJ- thanks for saying that.

I give people crap about using the search function because that's all I ever seem to do when I have a problem. I end up solving it through search and never get to take part in the half-assed socialization that is an internet forum. Something like that... man, I wish I was funny, and not so much an asshole.

sgtmack said:

If the compressor stays running, you have a switch problem. A vacuum leak will keep the mode doors from working, but the rotary switch will still turn the compressor off and on.

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