What can cause the heater in a 96 caravan le with duel climate control to blow hot air on the drivers and cold air on the passenger sideThe air condition in summer works fine?
I once ran into this on a 96 Caravan. The Chrysler garage had told the owner that the climate control computer was bad and a quote of around $1000.00. In my investigation, I found a quite different problem.
There are two stepper motors mounted on the heater box just above and a little to the right of the accelerater pedal. You should be able to see and hear each motor move independently as you move the pass/driver heat controls. In my situation, the motors both worked, but the plastic gear had pulled out for the drivers control.
The gear has a pie shaped array of teeth and a long (aprox 2-3 inch) snout. The snout slides into a hole in the heater box and on the end of the snout are two plastic tabs that snap into place to hold the gear. I don't think the tabs had ever been seated completely into place right from the factory and now with the tabs being held together for so long, they would no longer spring out and lock, so a new gear is required. This new gear was avail at the local dealer for 72 cents.
Now, putting the new gear in was a bit of a trick. First the stepper motor must be removed, (I believe there were three screws). The new gear slides into a sleeve and the sleeve must be held all the way out in order for the lock tabs to seat in and lock. When all the way out, the sleeve is flush with the heater box, so it is hard to hold. I was able to accomplish this with a dental tool.
You will know when the gear is locked into place, and you would likely have to break it in order to remove it.
On a final note, if you have the fan speed turned to low, you will probably be able to hear the stepper motors as you move the driver or passenger heat control. If you hear both, then you know the circuitry is doing it's job and the physics of the door moving in the heater box is not taking place.
Your problem could of course be something different, but your symptoms sure match what I had experienced.
Good luck on this.Rick