Hi All,
My wifes '06 is giving her some issues. Every now and then the drivers side heat will blow cold air. At first I thought it may be do to the fact that she normally has the pass. side her cranked up to 85 and the drivers side 70, but thats not always the case. WE were out the other day in her car, I was driving the temp for both sides set @70 and the drivers side slowly starts blowing cold air while the pass. side worked as normal. As I drove I played around with it, I ended up shutting the heat off then back on and it seemed to work right after that with both sides getting heat. I've done some reading on this, I don't think I have an air issue on the count of the passenger side heat always works. I also read somewhere about actuators for the dampers, I just can't afford to start throwing parts at it, so I'm here asking the folks who know. Thanks to all in advance.

Ben (in cold NH)

The actuators are electric and control the mode doors and they are controlled by the HVAC control head. It could be a bad temp sensor (there is more than one) or a faulty control head. There should be a self-diagnostic feature for the HVAC control head which lets you read the various sensors and check the mode door actuator operations. The procedure would be located in the factory service manual, of which there are downloadable versions available on the web. We have an '05 manual at this site, which should work in your case.

Thanks smj, I had some log in issuses, so I kinda took a stab at it after I read your post, heres what I know now. self diagnostic= 00, no faults found. I ended up buying the drivers side damper actuator and installing it, while in the process of doing that I got checking around some of the other maintenece items (battery terminals, air filter, fluid levels blah, blah) and what I found was that even though I have always made sure the coolant overflow always have juice in it, doesn't always mean that the radiator was full. Ive read of folks having probs with the heat at idle do to low level (air in the system) but that was not the case with our car. My issuse with this is why didnt to radiator suck it back from the overflow tank to keep its self full? Regardless, the wife reports back the the heat in her car is working much better, so which one fixed our problem is unknown, but my guess is the the damper motor

The pressure cap on the system is on the reservoir. The cap on the radiator is not and is really only used to fill the system during a service. The only thing that would cause a restriction is a blockage of the hose between the neck of the radiator and the reservoir. A kink in that hose or some sludge build up inside the hose or at the bottom of the reservoir could cause that.