I have a '07 Pacifica with 85k miles on it. It is in good condition and well maintained with no history of problems. When I try to heat or defrost the interior, it will not blow hot air although the the engine is up to temp. I can eventually get it working by playing with the various heater controls and giving it time. Once working, it acts OK until I turn the car off and then maybe, maybe not upon restarting the car. Any suggestions? Thanks

 

does it blow air out? hot or cold? if it just blows cold air and sometimes hot, the easy thing to do is check coolant and make sure you have enough. second, if you have coolant it could be two thing....one your heater core is clogged and when it warms up enough, it is viscous and has enough pressure to go around the clog. I am not sure if those diverter panels run off vacuum but if they do make sure there is vacuum to the ports. I have also see the panels sometimes get old and stuck and need to be replaced. I could go more in depth but that should give you a good place to start.