I have dual climate control that I believe is considered a manual (MTC) system as opposed to the automatic system (ATC). Anyways, the passenger side blows cold but the drivers side blows hot air when the AC is on. I read somewhere that you can reset/calibrate the blend doors by turning the key to the on position and then holding down the rear wiper/wash button and the recirc button for 5 seconds but this didn't seem to do anything. I see a lot of posts around the web regarding this issue but very few people have reported having any success with any of the solutions.

Any other ideas?

 

I'm taking a leap and guessing you have a 2001-2007 van. Here's the factory procedure posted at post #7 in this thread on this forum titled
ACTUATOR CALIBRATION/DIAGNOSTICS AND COOLDOWN TESThttps://dodgeforum.com/forum/dodge-c...formation.html

If this does nothing to help you probably have a dead driver's side mode door actuator.

 

Yes it's a 2002 Grand Caravan. I figured out how to complete the calibration - I need to hold down the power button and recirc button. I ran the calibration multiple times and verified that all actuators are working by watching them under the dash during the calibration test. So I'm guessing the blend door shaft may be broken (http://www.*********.com/forums/show...=235463)?????? Which actuator in the picture below is for the drivers side??

 

Based on this diagram and if the left side of your picture is the firewall then the drivers blend door is on the right. http://static.cargurus.com/images/si...7383943597.gif

 

Here's a video that I took during the calibration. Everything seems to be working and no fault codes exist after the calibration is complete. With the AC on, the air coming from the passenger side front and the rear is very cold but the drivers side is luke-warm. If I set the drivers side to full heat, then hot air will blast through the vents but when I set it back to cold, the air becomes luke-warm. It almost seems like the blend door is not closing all the way allowing some hot air from the heater core to be directed to the drivers side vents. How can I verify if the door is closing all the way without pulling the dash???

I do have a small AC leak on a rear supply (hi-side) line going to the evaporator. I did read somewhere that if the AC wasn't operating at peak performance, similar problems can exist like I'm experiencing. But it just seems odd that cold air comes out of the rear and one side, but not the other side. Cold or hot, the air should be the same on both sides.... unless the doors weren't operating completely.

 

First you deserve a medal. That's the first time in 8 years of cruising forums that I've seen someone get up in there and video those actuators moving. How's your back?

To me it looks like the actuator is moving correctly. The test monitors actuator movement but not whether or not the door has moved where it was commanded. That's probably why the test passed. I'd guess the shaft is snapped or the door is slipping on the shaft.

Verify the door is moving? Can't help you there. I've never dealt with it. Might shoot Tizzy1 a private message. He is a go to guy for anything HVAC related on these vans and may have a trick in his toolbox.

 

There is definitely no way to peer inside the housing unless maybe if I remove the heater core. But I removed the actuator and rotated the blend door by hand and it's definitely opening and closing. I can feel the door operating normally. So for now I'll seal the AC leak and recharge the system to see if that miraculously fixes the problem. I still fail to see how one side blows cooler than the other when the AC is on.

Does anyone have a diagram that displays how air is routed through the system? After staring at it for a while, it seems that air enters the system through the firewall and then through the AC evaporator whether or not the AC is on. If recirc is on, air will enter the system through the recirc door under the dash on the passenger side and is then forced through the AC evaporator whether or not the AC is on. Once past the evaporator, air is then blown through the cabin filter and then flows into the complex chamber that divides the air for the left and right sides, then routs it through the heater core if heat is on or bypasses the heater core if cold air is selected, and then finally through the vents.

So ALL air must be chilled by the evaporator if AC is on and heat is off - not some of the air, all of the air. It truly makes no sense to me that half of the vents blow luke-warm and the other half blow cold air.

 

I know it sounds crazy but you are right on the money. When the a/c system is low on Freon, you get cold are on the passenger side and warm air on the drivers side. Almost everything we build will do this. Can't explain it but have seen it hundreds of times and fixed every time by charging the a/c system to the proper level.

 

What is the freon capacity for this vehicle? 2002 GC w/rear ac. The tag under the hood is gone.

 

2.88 lbs if you have rear a/c, 2.13 lbs if you don't