not an a body but still a dodge more or less

Had a problem like this with my Durango this past fall. Took it to my mech. He un-did the heater hoses and back flushed the core with air pressure. Blew the crap right out of the core after a very short time. Heater works great now. Hope this helps you some. Worth a try if you can do it and a hell of a lot less work. Good Luck