my 1993 gm van's air conditioner works but will not blow out of the vents. it blows from the defroster and small vents in the console. I have been told it could be a vaccum leak, where do I look for vaccum leaks. does not matter if I change controls from defrost to heat or to air it doesn't change the air flow
Just a guess, but at least some GM's take the vacuum from a plastic cannister, probably located under the hood. I would look around there. Some of them are rather easy to snap off the little plastic connector. I have drilled them out and replaced them with brass or plastic hosenoses from the hardware store.
If it isnt at the cannister, you can probably trace the vacuum lines and hopefully find one cracked or disconnected.
Most definitely a vacuum connector. The vents are switched by vacuum-operated actuators; no vacuum, no switching. Do yourself a favor and do NOT pull anything apart inside the passenger compartment, dash, etc. It's in the engine compartment.
Look for hoses that are loose, brittle, or worn from rubbing against other parts. They should fit on the connecting nipples snugly; if not, replace the hose. With a car of your age, my procedure is usually to change 'em all. You can grow gray tracing vacuum hose leaks on an older car. Life's too short.
-= Larry A.
Open the hood and the vacuum reservoir is the large black ball shaped item attached to the hood to the right of the latch area. It has one line that connects to it. That line will go down to a check valve mounted on a short line toward the rear of the intake manifold (pull the doghouse cover for better access to it) On that valve is a second fitting that goes inside to the heater controls. Check all the lines and the valve and ball for leaks. The valve can be tested by blowing through it gently, if you blow into the side with 2 ports air should come out the other side. If you blow through the side with 1 port it should not allow air through.
actually, 93's use a stepper motor to control the ducts. if your a/c's controls have a digital display, is there anything flashing on it? that flashing will usually indicate a problem, but - like i said, on 93's, you don't even have to have the engine running to make the ducts change from floor, to dash, to defrost
- you adjust the controls, & you can hear the stepper motor moving the ducts. i was surprised too, but it's true.
The 95 that I have has vacuum controls for the heat/AC. Plus a control cable for Hot/Cold. 96 was the redesign year that included a lot of electronics.
The 95 that I have has vacuum controls for the heat/AC. Plus a control
electronics.
hmmmm, i wonder why my 92 has electric step motors that control the vents then - my a/c controls are electronic - there are no cables at all - the hot - cold control is digital, & you move it up or down on an LED type display (that will also blink out error codes when there's a problem). no vacuum anything in it (unless you wanna count the inlet side of the fan)
On a G series? That is a full sized van you have? Never seen one with electronic controls, even the factory book shows mechanicals.
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