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.
Improper HVAC Temperature and/or Air Delivery Due to Failed Mode Door Actuatoron GMC Sierra 1500
Average mileage : 109,061 (30,000–210,000)
38 people reported this problem
22 people shared problem details
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.
1999 GMC Sierra 1500164,322Visitor
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!
2001 GMC Sierra 150075,000Visitor
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
2004 GMC Sierra 1500114,000Visitor
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.
1999 GMC Sierra 1500127,000Visitor
System won't deliver to air flow to the proper place, ie defrost,floor,or ac vents.
2000 GMC Sierra 1500210,000Visitor
system won't deliver to air flow to the proper place, ie defrost,floor,or ac vents.
2001 GMC Sierra 1500151,000Visitor
Heat vent operation will only blow on the floor and windshield defrost. Does not change position when the nob is turned.
2000 GMC Sierra 1500145,000Visitor
textbook problem like all others. Temp. adjuster knob when turned to cold would only blow hot all the time. Actuator is at fault.
2003 GMC Sierra 150063,000Visitor
heat only at 90 deg.
2000 GMC Sierra 1500199,589Visitor
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
2004 GMC Sierra 1500155,000Visitor
Cold on passenger side, hot on drivers. Leave off for awhile and runs ok. Already paid to replace actuator door.
2004 GMC Sierra 1500111,000Visitor
After replacing batt. the air came out of the defrost only. Happened once before when I disconnected the neg. batt. cable. I gained access to the air direction valve, removed the motor, installed the motor on the actuator shaft and turned the motor by hand until the screw holes lined up and then installed the screws. All worked well until I had to replace the batt. I will do the same again.
2002 GMC Sierra 1500Visitor
the air flow for both hot and cold only goes to the feet and the defrost
2004 GMC Sierra 1500120,000Visitor
Air will be blowing cold and then just start blowing hot. Switching the truck off and back on usually helps.
2004 GMC Sierra 150088,000Visitor
A/C blows cool air, then suddely switched to hot on drivers side only. I have to shut off engine and restart to correct a/c.
2004 GMC Sierra 150030,000Visitor
Driver's side temperature control actuator causes hot air to blow when AC is on. Have to shut off engine and restart to get cool air on driver's side.
2003 GMC Sierra 1500110,000Visitor
no defrost, cold air only on passenger side , hot through vents.
2009 GMC Sierra 150081,000Visitor
My 3500 is doing the same thing
2004 GMC Sierra 150090,000Visitor
Passenger side vents will continue to blow cold air out of them while the driver's side vents blow hot air
2004 GMC Sierra 150045,000Visitor
When driving the driver side a/c vents starts blowing heat instead of cold air. If you turn off vehicle and start up goes back to normal. This is a intermittent issue for at least 5 years.
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