Mechanics

NON FUNCTIONING

2001 GMC Safari • 6 cylinder 2WD Automatic • 175,000 miles

Air conditioner working but air only comes out of top vent
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Sylvain amar
June 13, 2011.



The actuators are vacuum controlled. Check vacuum source.


JDL
Jun 13, 2011.
ALL VACUUM HOSES WERE CHECKED AND SEEM FINE?


Tiny
Sylvain amar
Jun 13, 2011.
There has to vacuum, can you feel the vacuum? If the hoses are fine and there is no vacuum, it won't work.


JDL
Jun 13, 2011.
THERE IS VACUUM AND THE AIR IS COMING OUT FROM THE TOP AND BOTTLE VENTS JUST NOT THE MANIN MIDDLE VENTS?


Tiny
Sylvain amar
Jun 13, 2011.
Below is the vacuum diagram. Check the vacuum to and from the actuator.


JDL
Jun 13, 2011.
Ok great than you veru much


Tiny
Sylvain amar
Jun 13, 2011.
The mode selection is done through a series of air doors that are operated by vacuum. When there is either a partial or total loss of vacuum, the system will default to either defrost or on some vehicles, heat. Acceleration can also have an effect on the doors for the same reason.

Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.


Wrenchtech
Jun 13, 2011.