Not sure if this is the place but I have a 1992 Camaro and am having a problem with the inside blower Defrost/heater/dash vents? The problem is the air is only blowing on top (Defrost Area) and I cannot get it to blow through the front dash vents or bottom heat area? I took the switch out and all the vaccum lines look great. I was told to replace a check valve in the motor compartment, after doing so it still does not switch. Any suggestions would be appreciated, I'm sure someone else has had this problem.

Thanks in Advance,
Tony

 

Hey, welcome to the site. A search will provide a wealth of info, as your problem is a common one: Defrost is the default when there's a vac problem. Stick your ear to the HVAC control head, pass side, and listen carefully. If you hear hissing, the problem may be the vac diverter valve.

JamesC

 

ok am havin this issue now myself.Take the heater control assem loose back it out and listen.Mine hisses right at the connections to the assembly.Thats part my problem, also found the rubber lines to the big ball under the hood are dry rotted and or broken so fixxin ta go thru and replace all the vacc lines under the hood.Another thing had this happen with my cutts and sumtimes the diaphrams to the lifters for the vent flaps ruputre so ya realy wanna just take a day and slooooooowwwwwllllyyyyyy go back thru all the system.A trick that has helped me b4 was to grab a baloon and blow it up and attach it to the vacc system (car not running)All it does is just pressureize the system in reverse not ideal but functional to find major leaks one can't hear with engine running and loud exhaust.Also i personaly don have a vacc device so have to think outside the box.I have used the wifes vacc to substitute the engine b4 but she got pissed.LOL.So plan ta get a shop vacc.Good luck...Bill

 

Thanks James, I can hear the vaccum leak. Will the dealership have the replacement parts I need?

 

I bought a used temperature controller switch on ebay and ordered the vac diverter valve from a local dealership here in Dallas. Should be fixed up like new here pretty soon. Thanks again for the help guy's.

 

did ya get it fixxed??
Dunno if this will help and probably too late but was refered to this pic and am gonna try to post it in here.

 

Not yet, still waiting for the control switch to come in the mail. When it gets here I will replace it. That diagram is awesome, I had no idea the inner workings of the system. Thanks a million, I really appreciate it.

 

wish ya best o luck.Havin same issues myself among others so plz give a holla if you get it figured out.Havin only defroster sux in the cold butt TN winters.

 

Bill, my problem was the vac diverter valve. If you take your radio out so you can see the bottom of the controls. Move you controls back and forth from max/Ac to defrost and you will see the center of the vac diverter valve spinning. Then put the controls on AC and gently push the center of the valve (the center part that was moving) to help it seal up and if thats your problem the air will start to blow out of the ac vents. Hope this helps you as well.

Thanks Again,
Tony

 

I forgot to add that the vac diverter valve is $25 at you're local dealership part dept.

 

Yes .

Glad you found the problem.

JamesC

 

You Da' Man!

 

ok thats part my problem too found the other leak in the engine compartment.That big ole ball thingy in the left fender.The hose to it was dry rotted and guess it was openin when the car bounced it.just gotta get the new switch/valve for the selector and all better. thanx guys.

 

Great to hear Bill!