2006 Grand Prix Blowing only cold air

[Siegel1719]

Both heater core hoses are hot to the touch. Car has digital controls so if I raise or lower the temperature settings there is no change in the temperature of the air coming out or the amount of air coming out. Is there anyway to test the HVAC switch itself to find out if its bad or if the blend door is bad?

Thanks
Jeremy

 

[Ponyryd]

Find the blend door motor and switch the temp while watching it (pass side lower?), if it moves you may have a broken door, happens a lot, if it doesn't move you have a bad motor or control head.

 

[Siegel1719]

I couldn't find the blend door when I removed the passenger under dash panel. I also did not hear or feel the door move. Also did not notice any difference in the amount of air flow through the vents as I would expect the A/C evap and the Heater core to have slightly different air flow rates.

Find the blend door motor and switch the temp while watching it (pass side lower?), if it moves you may have a broken door, happens a lot, if it doesn't move you have a bad motor or control head.

 

[Ponyryd]

Try googling where the blend motor is? Usually where I said but I've seen them in different spots, you likely won't hear or feel the motor working, they use nylon gears and are very quiet, you should however notice a change in velocity as you thought. Control heads fail, but the only way to test is to find the motor and check for command, unless you have a good scanner and can read the blend status, likely need a gm scanner tho.

 

[Siegel1719]

I googled it and it reminded me that I forgot to mention the car has dual climate control for each side of the car. So there is a two blend doors one for each side of the car. Both sides are blowing out cold air the same though so neither blend door is working currently. Would this point more towards the HVAC control being bad or something else?

Thanks
Jeremy

Try googling where the blend motor is? Usually where I said but I've seen them in different spots, you likely won't hear or feel the motor working, they use nylon gears and are very quiet, you should however notice a change in velocity as you thought. Control heads fail, but the only way to test is to find the motor and check for command, unless you have a good scanner and can read the blend status, likely need a gm scanner tho.

 

[Ponyryd]

Ya, bad control head would be very likely. Problem is, the head likely sends the signal to the BCM, which then sends it to the blend motors, so it tough to tell without a wiring diagram. Issues like this are often solved with new programming.