Want this question answered?
if im not mistaken the heater control has vacuum lines. take off heater controls and see if you have a bad vacuum line to heater box.
Check the heater valve and/or the controls to the valve. maybe a problem with the controls, most of them are run off of vacuum, if a hose has a hole in it, it wont work
You can find heater vacuum line diagrams for your Chevy van in most Chevrolet service manuals. The service manuals can be found at your local library.
The heater blend door is not run by vacuum. It is run by an electric actuator.
You would find the HVAC vacuum line routing in a shop manual for that vehicle.
this model does not have a heater control valve, it has a specail thermostat that controls flow.
lose of vacuum to heater deverter valve.follow heater hoses from engine to heater core valve has two hoses in and two hoses out and one vacuum hose.vacuum hose gose to tee then back to engine other vacuum from tee controls heater switch defrost to floor heat knob. replace all of these lines about 6 feet will do it.now the bad, you must pull back the dog house about a foot divers side to remove one vacuum hose just do it the first time and both problems should go away.
follow the upper radiator hose, that should lead you to it.
up your mom and around the corner
That vacuum line originates at a T fitting at the vacuum reservior (about a 5" black ball) located near the right front inner fender, about 2" forward and right of the engine block. A larger tube supplies the vacuum from the right rear of the upper intake manifold (plenum) fitting. This tiny plastic tube is prone to drying and splitting in the area that is exposed to engine bay heat before it goes into the wiring harness loom, so give it a good look over there. Also, the manual valve in the controls gets loose from use and will loose vac there, I've made special and cheap kits to repair this. On my '95 Astro I had only 5" of vacuum at the fitting on the plenum, a new gasket brought it back.
henry14@yahoo.comh
Check the following.......... 1. Vacuum leak, broken vacuum line or disconnected vacuum line. 2. A/C - heater inside car door operation.. 3. A/C - heater controller..