First I would like to say "HI", new to this website, but I've learned a lot already using the search option. Last week I searched on why my 4WD was not working. Found out that the small black vacuum resevoir attachted to the hood was broken. The little nipple that holds the vacuum line was broken off and just hanging there. Went to the wreckers and picked one up for $5.00, now it works great, just in time for the winter season.

Now to my next problem.

On my heater controls. My fan works on all levels, and the heat control works good (cold to hot settings). But when I want to change the direction of flow, ie. Defrost, face, floor or combination of two it doesn't change. It is currently locked on Defrost and Floor, no matter what I select it doesn't change from this setting.

I've tried tracing out the vacuum lines off the back of the controls, but can't find anything wrong. Any advice is greatly appriciated,

Jamie

 

The general concensus on here if you have checked the vac lines behind the controls is that the vac accuator is broken or stuck. I have had the same issue for a while now and need to get it fixed. It would be nice if someone out there had a picture or detailed diagram of the accuators locations. I have not had the time to field strip the dash and explore.

I hear hissing behind the controls but have replaced both the controls and vac line harness to the next connector back. So I am 90% the problem lies deeper in the dash!

 

Thanks for the reply, not sure where the vacuum accuator is located either. Any input from other people would be good. When I change the settings on the switch, I don't hear any vacuum passing going from selection to selection.

Could it be the switch itself, if not, it would be nice to know where this actuator is located, so that I could take a closer look. Have a Haynes manual, but it's not really helping with this problem.

Jamie

 

THIS POST will detail the vacuum controls for your truck. If you have vacuum at the vacuum source to the back of the HVAC panel, then you have problems elsewhere in the system. I am sorry to say this, but inorder to get to most of the actuators in the HVAC system, you really do have to pull the dash apart. Some of them are accessible with the glove box rotated down and out of the way. The color of the vacuum lines listed in the diagrams linked to above will identify the different actuators.

 

Thanks for the info swartlkk! Do you happen to know specificly if the accuator that controls the defrost/floor to dash vent can be accessed from the glove box opening? Since I think that is where my problem lies, as the hot/cold & A/C temps work as they should. And would the fact that I can hear the hissing most with the selector in the " floor" position?

Thanks Again!