I have a 2003 SS. I have the dual climate control. When the heat is turned on, it blows hot on the passenger side, and cool on drivers side. When i use the A/C both sides work normally and blow cool. My heater core is not clogged and i have replaced the thermostat. Any help would be appreciated!

 

I did a search for this problem on several web pages. The dual climate control panel when set to cold on both sides, functions normal. Turn the sliders up to full heat and the passenger side gets heat, but not the drivers side. On the highest heat setting, the drivers side still blows cold air.
First thought when there is no heat, is cooling system clog or thermostat.
The temperature gauge is normal, tho. Thought it might be an electronic issue, and replaced the panel since a bulb was burned out in it anyway. Nope. Didn't fix it. And I seen on those websites that dealers say it's a gate or door issue. When brought in for repair, the gate/door was fine. But after flushing the heater core it seemed to restore the heat again on the drivers side.
Would appreciate any suggestions from anyone on this issue. I put one of those Prestone Flush n' Fill kits in a while back, so I'm going to go out and get a couple jugs of antifreeze. Not expecting it to work, but it's routine maintenance that needs done anyway and then I can cross this of my list.

 

If you ever fix these please tell me how you fixed it. I'm having an issue with the driver's side AC not getting cold and I've replaced both blend door actuators. That's not the problem. Please keep us posted.

 

Have you checked to make sure your freon is full? Mine had a similar issue and found out that it was a leak in my condenser. I understand that the drivers side is first to lose freon so your passenger side may stay cooler a little longer than drivers.