When I put my heater on, the heat blasts out the A/C vents. The garage said it's the lower mode vacuum actuator, and I've read some other old posts here with the same problem.

The problem is that the guy said that part is discontinued, he can't find it anywhere.

Any ideas where I can get it? I think the GM part # is 1996688, but I'm not positive.

Thanks...

 

that doesnt make any sense.. the heater comes on... and blows out of the A/C vents? arent those the same as the heater vents?

now if the defroster wasnt blowing on the windshield i could see that as a problem but what you have is normal

 

You get it from your local buzzard.

Even with a part #, about all you'll likely get from GM, is blank stares or laughter.

Those rarely go bad anyway. Far more likely, the vacuum feed into the cabin is disconnected somewhere, or the little vacuum "switch" valve on the control head is bad.

 

The problem went away by itself for a few months, but it just started again. When I put the heater on, it comes out the AC vents. When I put the defrost on, about half comes out the defrost and half comes out the AC vents.

The guy at the garage said it was the "Lower mode vacuum motor", but the last post said it could likely be the vacuum switch. Are they attached? What should I ask the junkyards for?

Or does anyone know another resource?

Thanks...