I have looked high and low for answer to this question, and yet to find a decent one. I am hoping that perhaps someone here has some insight inot the issue.

The problem 06 RRS SC; driver side basically no heat. Out of the 4 vents I get heat out of 1, the left hand face vent, or the vent closest to the passenger window. My understanding is that there is one heater core, 2 heat blend motor actuators, one driver, one passenger, and two corresponding air flow actuators for driver/passenger, windshield and face and footwell.

What I know is that all the physical vents provide proper air flow, so I do not have a blockage issue. I also would have to assume that since I am getting heat from one of the face/footwell vents that the heater blend motor is functioning, if not properly, sufficient enough to distribute heat to the drivers side ducts. The previous assumption is supported by the fact that when I turn on the AC I get ice cold air from all vents. I would also make the assumption that the air flow door actuators are working properly as I can control the air flow using the heater control panel.

So what the heck is going on here? How is it possible to get some heat through one vent and not the others when the heat is coming from the same duct?

I have changed more than a few heater cores in my life, and never had a issue like this before, but this is the only logical answer I can come up with; the heater core is partially blocked and this is affecting the heat distribution, and when I say that I think this makes no sense.

As well I did do the diagnostic test and it appears I have a issue with one of the doors, even though they appear to be working, and sometimes when the heater first kicks on I get heat for like 3 seconds from the right hand face vent, but then it immediately goes cold.

Any help anyone could give me on this issue would be greatly appreciated. I want to make sure that when I go through all the trouble to tear apart the car to fix this issue that I am covering all my bases, and I would prefer not to have to pull the core and swap out all the actuators if I really do not need to spend the money on all those parts.

Thanking you in advance for any help.