I have a 95 chev Balzer. I can't get the air to exit the panel vents, it is stuck through the defroster and floor vents. I hear the hiss of air escaping from behind the dash. I have checked/changed the vac tubes coming to the vent controls as well as the vent controls themselves. Does anyone have a diagram or picturs of where the actuators are? I can get to the one under on the far passsenger side and it seems to be fine. Any help would be great!

1995 Chev Blazer 4d 4x4 4.3

 

I had the same problem. Look under the hood and where the round canister is mounted to the hood, follow it down and it goes to athree wayvalve it has probably gone bad. You can bypassthe canister and go from the motor to the hvac system but when you hit the throttle the system loses vacuum and it switches back to defrost.

 

peegh, Thats a good description of what you need to do, I had that problem but I was able to fix the valve before it was completely worthless.

 

Thanks! I will give that a shot tonight.

 

You would be better to replace the switch with the new replacement, GM has a service bulletin for the switch and a new designed version. What is happening is the seal in the 4x4 switch on the transfer case leaks vacuum and can suck up fluid from the transfer case into the HVAC control head, you can check your ashtray under the control head to see if there is any fluid film in the ashtray. If there is fluid there then you may need to replace the HVAC control head also...

 

I have not had a chance to check the "T", but I have replaced the HVAC head unit. Did not fix the problem and there was not fluid in the ashtray. Thanks though Mark!

Is there a good way to test the 3-way valve?