05' Malibu no heat?

[MalibuBob]

I've got an '05 Malibu (the new body style) with the 3.5L V6 that has about 92K on it.
On the way to work yesterday, I was playing with HVAC controls, and noticed that even if I turned the heater control all the way up, the air coming from the vents never got very warm.
I know that sometimes this condition is caused by a malfunctioning thermostat, but I don't think that's the problem since my engine temp gauge consistently stays about in middle. Since it's summer, I imagine I would've seen some overheating problems if the thermostat wasn't working.

Anyone have any ideas on what to check next? I'd like to get this fixed BEFORE I really need the heater!

[Jetex]

I had the same problem on my 04 Malibu. The fancy "pulse count" motor for the heater door was defective. I think you'll have to take it to a dealer for repairs.

[wpbharry]

The thermostat on my '04 Maxx went last December and there never was any change in the temp guage.

[MalibuBob]

I checked a few things I found while searching the 'net about this problem and none of them seemed to be the problem, but now the problem is fixed. The temperature control works just fine... I have no idea what happened.
Thanks for the suggestions!

[Jetex]

I'm still sure the pulse count motor or the circuitry for the heater door is the culprit. If it happens again do this - switch ignition on engine off. Turn heater control to max and then min and listen if the motor runs. The motors for the climate control are set by a small computer. It's possible that the computer got hung up. Restarting the car might have reset it.

The coolant circulates at all times through the heater core. The position of the doors on the climate control determines the temperature of the cabin.

[Jetex]

Here is more information about the latest circuitry for climate control.

https://delphi.com/shared/pdf/ppd/he...c_controls.pdf

[MalibuBob]

Thanks Jetex.
When I was trying to figure out this problem, one of the things I did was to pull the battery fuse for the HVAC system. I had read that doing that would "clear" the controller that operated the pulse motor. Maybe that was the solution this time around.

[Home Mechanic Tech]

Remove the Blender motor and snap the DC motor back in place.

[Jetex]

I don't quite follow you HMT. Could you please explain?

[eceavchss]

I had the same issue with my 04 Malibu. No heat and couldn’t adjust the temperature for the AC. The fault is with the air temp actuator located on the driver side of the HVAC/heater box in the dash board. The parts itself is about $50 and the dealer’s bill will be around $225.