Question about Cars & Trucks
2003 gmc Yukon 5.3 ..2WD air conditioner blows cold air out of floor vents and defroster vents but not the vents in the dash
Posted by Anonymous on
A vacuum hose that controls the little door that switches where the air blows from is off, its gonna be a real chore the find which one and take the dash out to get to it, but you might get lucky and be able to look underneath the dash from the passenger side and actually see it, good luck
Posted on Jun 19, 2010
I believe this vehicle uses stepper motors to control the vents, not vacuum lines.
A stepper motor reports back to the control module what position each flap door is in. (i.e. heat, cold, loor, defrost, etc.) When power is lost, the module forgets these positions. You will need to reset the AC system so that it relearns the positions of the doors. Search for "how to reset AC system" it involves pulling the fuses for the AC and reinserting them in a particular order so the system can determine the positions of the flap doors.
Posted on Jun 23, 2012
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