I have a 2010 AWD Touring, 3.5L. 100,000 miles. Separate driver and passenger temperature controls. System includes automatic option.

Here are the facts:
A/C system and A/C button both work.
Blower fan and blower dial work, including at different speeds.
Mode selector / control works (front windshield defroster, floor, body, mixed mode, etc.). The air blows out of the appropriate orifices when I change the **** to different settings.
The two hoses (supply and return) coming from the radiator to the firewall to supply the heater core are nice and hot after I've been driving. So I don't think the hoses/pipes are blocked.
No steam out of vents or leakage from the heater core that I can discern or notice. So I don't think the heater core is cracked.
When I try to get heat, with both driver and passenger temp settings to highest temp, I get tepid heat (if you can even call it heat!) out of the drivers side vents, and cool air out of the passenger side vents.
Sometimes when I turn on the heat, it blows hot for maybe 3-6 seconds.

Here are my thoughts:
So I am thinking maybe BOTH the driver and passenger temperature door actuators are broken? Or the control device that reads the temp I turned the temp dial to and sends that info to the temp actuator? I am not sure of the proper terms here..... It seems unlikely they would both be bad....

Any thoughts? Help! I am reluctant to take this to the shop yet since I am not convinced their diagnostic efforts won't just be to rip everything out and replace it all.....

Thank you!

 

Sometimes when I turn on the heat, it blows hot for maybe 3-6 seconds.



clogged heater core

 

Thanks. I was assuming since the two hoses entering the firewall were both hot that the heater core wasn't clogged. Can it still be clogged with both hoses hot?

 

In a word...YES. Both tubes run from the same "tank" of the heater core and coolant is nor flowing thru the small tubes of the core itself.