I could use a little help with a vacuum problem I have. Well on the way back to NJ from FL I find that it is starting to get cold, so I decide to turn the heat on for the first time in two years only to find it is blowing cold air. So today I tear the dash all apart to check things out and the heater core gets hot. The blower valve won't move no matter what position the **** is in. I checked the diaphram and that is fine and there is the usual sucktion noise when I move the **** to OFF so there is apparently vacuum to the ****. I decided to trace the vacuum line under the dash in the wiring harness and it goes up to the headlights on the passenger side and is connected to nothing. Could this be why the blower valve won't move? If so, what the heck is it connected to up at the headlights? Someone help me out here, I'm freezing...

 

There's a vacuum reservoir mounted under the right headlight, near the horn assembly. If you're hearing the vacuum "sound" when you switch your heater control to off, sounds like the system is getting vacuum.

 

It sounds like the HVAC controls are good, and that the vacuum is good. That leaves the check valve. Inspect it for cracks, or leaks.

http://shbox.com/1/vac_check_valve.jpg

Courtesy of Shoebox.

 

OK, I took the whole bumper apart to see if I could find that reservoir and there's nothing there except the horn and a discoloration in the paint and a threaded hole where a vacuum reservoir should probably go so I just plugged the vacuum line. The check valve seems fine and yes the system is getting vacuum. The blower valve still doesnt move no matter which position the ***** are in. That is what determines how much air is pulled from the heater core, right? It's not the temperature **** with the cable is it? Man, I really need to get this figured out, it just snowed and I am freezing my a** off.

 

Got it fixed, thanks anyway guys. The temperature control **** is kinda stiff for some reason, always was, but it looks like it rounded out the ****. Just gonna use a pair of pliers until I can get a new one. Wish i had come to this conclusion before I took my dash apart .