Problem Description and Possible Solution
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.
Average mileage: 123,886 (2,010–311,149)
15 model years affected: 1999
, more2003, 2004, 2005, 2006, 2008, 2009, 2010, 2011, 2012, 2014, 2015
147 people reported this problem
When selecting where i want my air to go, it only comes through the vent at my feet and through the defrost. The dash vents do not blow any air. It seems like a common problem. Im gonna go ahead and replace the mode actuator!
A/C only cold on passenger side. Drivers side blows hot. There is no adjustment on the drivers side for temp. If you turn off the truck and then restart, it might work for a bit or not.
Turn on heater and it only blows cold air
System won't deliver to air flow to the proper place, ie defrost,floor,or ac vents.
A/C works great but won't change to heat when required.
a/c blows hot driver side/cold passenger side. may start cold both sides then driver side starts blowing hot and getting hotter. passenger side continues to blow cold air. tried recalibration, pulling fuses, restarting, stopping vehicle turning eng off and restarting eng and then a/c same results.
system won't deliver to air flow to the proper place, ie defrost,floor,or ac vents.
Can't change heating/a/c temp unless I shut down truck and reset to desired temp and restart, then it goes to correct temp
Air will be blowing cold and then just start blowing hot. Switching the truck off and back on usually helps.
Air blows out the vents for about 20 mins, then it starts blowing out slower and soon it is blowing out in the ducts, but not coming out anywhere, (vents, defrost or the feet ) .
Heat vent operation will only blow on the floor and windshield defrost. Does not change position when the nob is turned.
Won't switch from,cold to hot, stays on air conditioner all the time, won't switch to heat, replaced the blend door actuator and it still does it. What else could be wrong?
This is a well documented problem as you can see by reading articles throughout various internet sites. For being the so called a "Professional Grade", I have had so many problems with my GMC, from the instrument cluster, steering column, bed liner, hubs, ABS, emissions, etc.... and now with the HVAC - I'd give my 2004 GMC Sierra a disappointing "F". GM needs to issue Campaign to correct this problems, since so many of their customers are experience problems due to their poor workmanship or inferior design.
blows out vents and floor only no defrost. previously could here groaning sounds coming from passenger side all the time while driving. took dash apart , flapper behind glovebox swings loose
textbook problem like all others. Temp. adjuster knob when turned to cold would only blow hot all the time. Actuator is at fault.
Air only blows out top/forward facing vents. Is not responding when I switch blower to defrost or floor vents.
the air flow for both hot and cold only goes to the feet and the defrost
I haven't fixed it yet, but when driving with Air conditioning running, just the drivers side gets hot, the passenger side stays cool. I pull over, turn my truck off, then I continue on my way. This happens 3-4 times in a 50 mile trip. I've checked with different places & it will cost anywhere from 200.00 to 600.00 to fix.
i have problems when i u the air or heater.i have to shut the car off for half hour before i can u the other