A/C and Heat only through top and bottom Vents
 

Hey guys. I have a 1996 blazer and for some reason when I turn the heat or the a/c on, it only blows the air through the bottom vent (where your feet are) and the top vent (the defrost vent at the top of the dash).

No matter what setting I put it on it always blows through just those two vents. It has been like this since I bought it about a month or two ago.


The A/C doesn't blow cold air but I doubt that has anything to do with it.

Winter is coming and it would be nice to get some heat directed to myself instead of the front windshield and my ankles.

Anybody wanna help me out on this one?

I would assume something with your blend door actuator is messed up.

I think I've read a little about those....are they located somewhat by the gas peddle? Is so, where exactly? Also how would I tell if thats the problem?

Thanks a lot for your help, Im just so eager to get this fixed once and for all.

Ok, scratch that last comment I posted....

There are 3 mechanical door actuators and 1 electronic door actuator right?

Based on what I originally posted, which actuator would it be?

http://i11.photobucket.com/albums/a1...7_hvac_sch.gif

Based on that diagram it looks like it would be the first actuator (first one on the left) since i have heat and a/c to my defroster and and by the pedals but not to the vents?

Can somebody with in debt knoledge of this pleace chime in and assist me?? Am I on the right track?

I believe it would be the far left.

haha, i kinda have the same problem. Except mine only blows at me and wont blow at my feet nor defrost the windshield

Cool, lets swap cars for a month :icon_razz:


So, does anybody else think that its the actuator on the far left in that pic that I posted in that link?

All I need is a few more "yesses" and im off to autozone to buy the part and install it on thursday.

It sucks though because I took my dash off 2 weeks ago when I replaced the heater core :icon_shrug:
If I had known what I knew now lol

On my 2000 Blazer the air only came from the dash vents no matter the setting. I found under the hood on the driver's fender behind the brake lines a vacuum hose not connected. From searches on here it said that there is a vacuum canister in the fender, for right now i have capped it of and all the settings (defrost, floor, vent, and max a/c) works. :icon_bike:

I just found the same exact problem!!! I hooked up the unconnected line to a different vacume source and it worked!

Now, does anybody know where those lines that come from the vacume canister connect to???

I just had the same thing happen with my 89. The vacuum lines in blazers run cruise control, the 4wd actuator that engages the front wheels, and the a/c.

By the way, on the canister there should be either 2 or 3 ports.
If it is two ports, one line goes to the air intake on the throttle body, one goes to the gas tank.
If it is three, one goes to the air intake, one is a breather that goes to the atmosphere, and one goes to the fuel tank.

This happened on my 2000 Jimmy. The canister only has one line coming out. You can see the vacuum line tee off from engine, through firewall and to canister. If you feel below/behind the brake cylinder you can feel the canister nipple. It protrudes into the engine compartment, so you dont have to remove anything, just plug it back in.

I have a 96 i just got about a month ago. First problem: I cant find the other end of the vacuum hose from the front diff actuator. Second problem: only the defrost vents work. i cant find the canaster or the vacuum lines near the brake booster. Any help? i spent the last hour or so searching and no luck!:icon_hyper:

Dont know anything about the front diff actuator 4wd am assuming. I'm sure someone on here can help though. On my vehicle you cant see or even feel for the canister. It is in the fender directly behind the brake master cylinder (on the side of the engine comp, drivers side) If you feel behind/under that brake cylinder you can feel a small nipple protrude from inside the fender to inside the engine compartment) That is the connection for the vacuum canister. Of course you will only feel the nipple if the vacuum hose is disconnected from it. If thats the case the hose has just pulled from it, pretty common from what I understand, and should be dangling somewhere in the back drivers side corner of the engine compartment. Again, this is experience of the same problem with a "different" vehicle. Not sure if above will apply.

Front air vents only
 

I am having a similar problem with air only blowing out the front vents. I get a lot of heat when stopped but as soon as I start moving the temp drops off. When I get to highway speed I need to turn the heat to maximum to getting any warm air at all. Any suggestions on how to fix this problem?