I realize this is Chrysler, but I believe that Chrysler makes the Dodge Caravan too.

I have 1999 Dodge Grand Caravan 3.3L. Heat control over the past year has worked sporadically. Finally it has totally stopped working. I do not have the dual zone climate control. Only one temp. control slider **** on Heat/Ac control panel. Have rear defrost and wipers.
All functions from the Heat/Ac control panel controls seem to work except for the temperature control. Took the panel off and messed around with it. Clean up a couple of places that looked like they might be corroded some. Installed it back and all of a sudden I have heat again. But only heat no control over the temp. Turned the van off and back on and now it is just cold again. This verified to me that something was going on with the Heat/Ac control panel temp. control. Purchased one from the junk yard. Unfortunately still had same problem with same symptoms.

Found the blend air actuator valve. Removed it and was able to manually move the blend air door to allow heat. However the door will only stay in the heat position when I have manually changed it and the blower is turned up to keep the door open. As soon as I turn off the van or turn the blowers off the door shuts or goes to the cold position.
Purchased a new blend door actuator valve. Still no luck only cold air.
Found calibration for a 1998 Chrysler Town and Country. Ran the following.
Set blower motor on high
set mode position to panel
open all a/c outlets
set temperature to cold
depress Wash and Rear wiper button simultaneously for 5 seconds
the calibration goes thru and all lights turn off. Still only cold air.

However, when the calibration first starts I DO FEEL HEAT and then back to cold.

Is the blend actuator valve out of calibration. I can't remember for sure but I think I may have had the ignition on when I hooked up the actuator before I got it installed. If so is there a way to recalibrate it?

Please help