One or more heater & AC (HVAC) temperature and/or air delivery mode door actuator may fail, resulting in improper temperature or air delivery. If this occurs, fault code(s) should be stored in the HVAC control module which should assist in diagnoses.Google+
Car Problem Reports
GMC Yukon XL 1500 Heating and AC Temperature and Air Delivery Mode Door Actuators May Fail
GMC Yukon XL 1500 Problem
Average Mileage: 134,947 mi (60,000 mi - 215,000 mi)
Visitor, 2004 GMC Yukon XL 1500, 162,000 mi
Rear heating vents only deliver cold air
Visitor, 2003 GMC Yukon XL 1500, 165,134 mi
my yukon blows hot and cold at the same time. only in the front of vehicle driver side cold & passenger side hot.
Visitor, 2001 GMC Yukon XL 1500, 215,000 mi
rear a/c blows hot air even when air is on
I have to go to full hot to get heat...if I back off even a little, cold air blows out of the vents.
Acuator failed had replaced cost $600