Trying to get my ac working.Only blowing hot air but not out of the vents.Whats up?

turboterror

Member
Joined
Dec 19, 2007
Im in the process of trying to get my ac to work. I charged the compressor and it cycled on, the electric cooling fan came on too. My problem is that it is only blowing hot air. My fan control and speeds all work. It wont blow any air out of the vents, (It is hot anyways) it seems to blow a little air out of the defroster vents.

Im assuming that there is a door that is not opening and that its either controlled by a cable of by vacuum? Where can I look to confirm the operation or lack there of the of ac/ heater controls? I would guess its behind the dash but my question is where and how do I access it and what do I have to remove?
Any help you could provide would really help.
Every day brings me closer to having this car fixed/finished.Thank you!!
 
doors are vacuum controlled

black hvac check valve at rear of driver valvecover with three ports
large port goes to source (tee'd to egr feed)
top port runs to ac controller and side port to the vacuum reservior ball under driver fender (also cruise if you have it)

with car off if you pull the line to the ball it should be holding vacuum (listen for hiss)

no vac when pulling line either the lines are leaking , the check valve is bad or the controller is damaged
though not a defect another possible could be the black white boost check valve to the hvac check valve is in backwards

there is service part for the controller available at most parts stores , its a black plasic flat circular selector assembly and located at the rear of the controller head by glovebox (has all the vac lines going to it)

another common problem you could have is a broken heat selector door pivot
drop the glove box and look to the top of the ac box in back
there is a black pivot arm with a metal rod and youll see the cable that runs to the controller
it should move when selecting from hot to cold
 
doors are vacuum controlled

black hvac check valve at rear of driver valvecover with three ports
large port goes to source (tee'd to egr feed)
top port runs to ac controller and side port to the vacuum reservior ball under driver fender (also cruise if you have it)

with car off if you pull the line to the ball it should be holding vacuum (listen for hiss)

no vac when pulling line either the lines are leaking , the check valve is bad or the controller is damaged
though not a defect another possible could be the black white boost check valve to the hvac check valve is in backwards

there is service part for the controller available at most parts stores , its a black plasic flat circular selector assembly and located at the rear of the controller head by glovebox (has all the vac lines going to it)

another common problem you could have is a broken heat selector door pivot
drop the glove box and look to the top of the ac box in back
there is a black pivot arm with a metal rod and youll see the cable that runs to the controller
it should move when selecting from hot to cold

Thanks so much for the intell, Im going out to check those things youve mentioned and see what I can find. It is very helpful to tap into someone elses knowledge,especially when most on here and very familiar with the g body regals.It is friggin so hot it is miserable here in Tennessee!! Thanks again so much!!
 
Easy way to tell if it's going from the heater to the evap is move the lever from hot to cold. You should be able to hear it open and close.;)
 
No its not opening or closing, I can feel it moving a little but not enough. I can always hear a hiss or the door open or shut on my other vehicles when I change from hot to cold or vice versa.
 
No its not opening or closing, I can feel it moving a little but not enough. I can always hear a hiss or the door open or shut on my other vehicles when I change from hot to cold or vice versa.
The hot to cold is done by a cable on a G body so it sounds like the blend door lever is broken or the cable is damaged.
 
Ok so I pulled the glove box door off along with the panel underneath it. The lever wasnt being moved far enough so I moved it by hand. I also noticed a door there but it does not move.If I push it in manually by hand air still does not blow out(hot or cold) Is there another component that I should look for? Everything still looks to be intact. My selector is not doing exactly right(it turns off the fan when I put it on high) but Ive ordered another one of those off ebay.
I am unsure where else I should look, Im guessing there has to be a vacuum line running through the firewall from the engine but I havent found it. Suppose I should verify suction is present
 
If y ou moved the lever by hand did you hear a clunk as the door moved? If not then the lever is broken.
 
If you don't hear the clunk, then try this:

First off open the glove box door. Remove contents of glove box. Push in on the metal hook tab on the left side of the door that holds the door from flopping down when the glove box is opened. Allow door to flop down.

Now look ahead inside. Notice there's a threaded rod that has a white plastic piece on top it, and a black cable that runs to it. A press on round flat metal washer looking clip holds the cable on. CAREFULLY remove this clip.

Now make sure the rod is pushed all the way in. This puts the HVAC in the cool mode. See if this fixes your issue.

When the threaded rod is all the way out, that puts it in the heat mode.

I had a similar issue as yours in which the plastic tabs that secure the HVAC cable sheath to the blower box, broke, which would not allow the blend door to fully operate. Once I did the above, I quickly diagnosed the problem, in addition to doing a temp fix; I had to reach inside to adjust the rod to what I wanted prior to driving off, but at least the heat/air worked enough to get me by until I finally replaced the cable.

HTH.
 
If you don't hear the clunk, then try this:

First off open the glove box door. Remove contents of glove box. Push in on the metal hook tab on the left side of the door that holds the door from flopping down when the glove box is opened. Allow door to flop down.

Now look ahead inside. Notice there's a threaded rod that has a white plastic piece on top it, and a black cable that runs to it. A press on round flat metal washer looking clip holds the cable on. CAREFULLY remove this clip.

Now make sure the rod is pushed all the way in. This puts the HVAC in the cool mode. See if this fixes your issue.

When the threaded rod is all the way out, that puts it in the heat mode.

I had a similar issue as yours in which the plastic tabs that secure the HVAC cable sheath to the blower box, broke, which would not allow the blend door to fully operate. Once I did the above, I quickly diagnosed the problem, in addition to doing a temp fix; I had to reach inside to adjust the rod to what I wanted prior to driving off, but at least the heat/air worked enough to get me by until I finally replaced the cable.

HTH.
Hey thank you for the in depth instruction Turbo T, I will do like you said and see what happens. Youve been alot of help to me and I appreciate it. Maybe youll be able to make it to the gs nationals in bowling green and I can buy you a cold one. Its nice to have my car running and driving, truly it is.
 
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