*Heat On*: Heat blows on passenger side, cold air blows on driver's side
 

I've found a few older threads dealing with similar issues, but nothing exactly like what I'm dealing with. When I bought my '03 last February, I noticed that (with the heat turned up) I was getting cold air out of the driver's side vents, but hot air out of the passenger side vents. Now that it's cooling down in Tennessee, I need to address the issue before winter.

My truck is an '03 Limited 4wd v8... I've fooled around with the settings, and am getting the following issue: With the climate control turned up to 80 or "Hi", I get really hot air coming from every vent/floor vent/defrosting vent to the passenger's side of the center console, vent on the driver's side blows cold air, like COLD air. Where it really messes with me is defrosting, since I can't defrost the driver's side of the windshield because of this.

I've read some things about cleaning or replacing the heater core, but I'm leaning more towards a stuck blend door somewhere, since the heat is CLEARLY working on the passenger side. Is there a blend door somewhere that divides the passenger/driver "compartments". Any advice appreciated!

I have a similar problem. When I turn on the A/C, the passenger side is cold and the driver side is warm. The driver side is also much weaker than the passenger side. Following.

Sounds similar... oddly, my AC works great on both sides, it's only when the heat is on that I encounter problems.

Have the AC charged with freon by a professional tech and a dye to look for leaks.

What was the solution?