i have a 2006 gmc truck , some time the driver side put out heat other side is still cold . turn off truck and back on and back to both sides cold like it should be.

thank you;

The heat in that vehicle is controlled by a blend door that regulates heated air flow. it is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.




78 Corvette Pace Car For Sale-18k mi orig-Florida

i can control the heat . it does not do it all the time.

how to check the blend door?

To add suggestion:

Make certain coolant is full. If not there's a problem to be found and fixed with why it's low if low,

T
_________________________________________

Tom Greenleaf - MetroWest, Boston

If it is determined that the blend door is stuck or jamming, then the entire dash has to be removed from the vehicle along with the entire HVAC housing to be able to access it. It's not an easy thing to repair at all.




78 Corvette Pace Car For Sale-18k mi orig-Florida

i can control the tempure. it does this every two days are so. when you turn off the truck and back on it is back to normal. can it be the controls?

Hey - know WE aren't there making observations and Hammer is a true pro at this.

My suggestion is to rule out low coolant level first and we can go from there. It's too new for me to know. You may have a radiator cap on radiator or pressurized and remotely. If the pressure cap is remote to rad then squeezing upper hose while cold may show bubbles to the recovery tank which it shouldn't! Yes, diverter doors and controls COULD be the issue and would take some diagnosing - tough if it won't stay broke "if you will" when testing for stuff!

T
_________________________________________

Tom Greenleaf - MetroWest, Boston

Tom
He's not dealing with a coolant issue here since his problem is lack of cooling, not lack of heat. It's the A/C that he's losing from one side.

Poster
As I stated in the beginning, the blend door sticking is the likely cause but I can't gaurantee you anything. The system needs to be checked out by a competent tech. This is not a DIY job and requires expensive equipment that you don't have..




78 Corvette Pace Car For Sale-18k mi orig-Florida