Jeep Grand Cherokee (2003) Dash Vents Not Working

I have a 2003 Jeep GC V8. It has about 100k miles on it.

Since it’s January (New Orleans) I haven’t used the AC or Heater much, but this morning it was hot so I tried the AC only to find that only my floor and defrost were actually blowing air.

I tried at all speeds and checked all vent openings, but got the same result.

Nothing registered on the Scanner and no check engine lights. Any ideas? Thanks! -Fletch

FYI, the CEL is not going to indicate climate control problems. I can only give you very general suggestions. The dampers that control the air flow are electrically or vacuum operated. You have a bad damper motor, a stuck damper, a control panel failure or something in between. The something in between is a vacuum leak or an electrical fault. All that stuff can be very difficult to check out because it is all stuffed behind the dash. I would start with what lies directly behind the controls, not because it is likely the problem, but because it is easy to get to.


Thank you for the advice. I got frustrated and hit the Jeep with my one good hand…so the wife made me take the Jeep to my mechanic this morning. After greeting me with the usual, “Not you again”. He spent an hour replacing the vacuum line. Wasn’t too $$ expensive other than the doctor’s visit for the hand. Thanks.

Common problem with the Cherokee is that the diverter flap for the heater breaks. Do a web search for Heater Treater - a DIY fix that is MUCH cheaper than the dealership fix.