Mechanics

AIR FLOW

1998 Jeep Grand Cherokee • 311,000 miles

My air diverter is stuck in the defroster mode and will not change to the front vents of the floor vents. The air conditioning works great, just will not divert properly. I have taken the entire front off the dash and exposed the heat/air unit, removed the controls and inspected the connections, and now puzzled what to do next?
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MichaelKersey
July 5, 2013.




This is a real common problem and most likely you got very carried away. If the controls and actuators are run by engine vacuum, the system will be spring-loaded to default to defrost mode for safety. Your feet might freeze but the windshield will be clear. Look for a small hard plastic vacuum hose broken under the hood or disconnected. There will also be a small check valve in that hose near the firewall. Be sure the hoses didn't pull off of that.

Caradiodoc
Jul 5, 2013.
Thank you very much. That was my next move. I'll put it back together.

Thanks again,
Michael
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Tiny
MichaelKersey
Jul 5, 2013.
You're welcome, but before you go through some more work, be sure you really do have vacuum controls and not electronic. You'll see various-colored plastic hoses going to the actuators from the control head. If you have actuators with two electrical wires, you have a computerized electronic system and you may still have a problem in the dash. I'm not really an expert on diagnosing those but I do know how they work.

Caradiodoc
Jul 5, 2013.

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