Chrysler Repair/1999 town and country no heat
My friend has a 1999 Town and country with over 200k miles on it. His heater has stopped working. The blower is fine and both heater hoses get warm and heater core has never leaked. His lights have been blinking for at least a year(the rear wiper and intermittent as well as the air and recirculate) The heater just blows cold air now. It seems as if the vent is closed not allowing the air to flow over the heater core but not sure.
I believe your theory is correct as to why no heat.
There is either a single blend air door that controls where the air is directed between the heater core and the ac evaporator core OR if the system has a driver and a passenger separate temp control option then there are two such doors. The doors are operated electrically via 'actuators' that are powered by the body computer in response to setting chosen at the conrol panel. So it is reasonable to believe that one or both of the actuators is not working of the door(s) are stuck in the ac position. You can get to and observe the actuators by removing the under-dash panel that conceals the steering column*. Once that is done you look to the right, toward the left hand end of the HVAC box, where you will see either 2 or 3 actuators. The upper rear actuator controls the door that changes the air outlets. The lower 1 or 2 actuators are the blend door(s); if two the forward is for the driver heat setting the rear one if present is for the passenger heat setting. You could change the setting and should be able to see the stub of the shaft rotate or not. If not, remove the actuator and see if the door is stuck, or the actuator drive gear doesn't move. The actuator is replaceable as it has an electrical plug.
There is a self-diagnostic procedure to test whether the body control module has noticed the problem but I suspect it will corroborate that the explanation is the blend door actuator(s) that is the cause of the no heat situation, given that there is good flow of coolant to the heater core. If you want to nonetheless do that let me know.
Please 'rate' my answer (see below),
*To remove the underdash panel you remove the screws that hold the parking brake release cable handle, then remove the cable from the handle, then remove the screws to the right and left hand sides of the panel and the screws at the top and bottom and the panel should drop down for removal. If the vehicle has ABS then you will find the control module of that is in the way of seeing the actuators so unplug that and remove it.