AboutDavid Hill Expertise I can answer questions concerning automotive air conditioning systems, residential air conditioning systems and electrical repair questions.
Experience I have 16 years of experience in the automotive air conditioning arena and am currently an instructor for H.V.A.C.
Education/Credentials I am certified through as a universal technician under sections 608 and 609 of the C.A.A.
Expert: David Hill Date: 6/30/2008 Subject: Dodge a/c
Question I have a Dodge Ram 1500 1999.When i turn the a/c/ on it starts to blow cold and then it sounds like a flap slams under the dash and it then blows hot. What do u think is the problem?
Answer Gary,
Thanks for the question. That flap slamming under the dash is your blend door closing. The blend door is what separates the heat from the heater core and the cool from your evaporator.
Now what could be making it close up? COuld be many different things. If your system is operated by vaccuum lines, then it could be that one of your lines has a serious leak, the actuator itself on the door may be extremely weak, or even the vaccuum control manifold may be going bad on it. And the suction force that is created by your blower motor itself is overpowering the vaccuum signal, "slamming" it closed.
If your system is operated by an electronic logic system, then I would say the your control head is sending the actuator the entirely wrong signal and may need replaced. Or again, it may be the actuator that is the culprit and once again, the suction from the fan is overpowering it.
Either way it is a rather in depth job repairing or replacing the vaccuum control manifold, vaccuum lines, and the actuators (less for the actuator, but still a painin the neck) I would recommend taking it to a reputable shop that you have heard does good A/C work and allow them the opportunity to troubleshoot and repair it. There are alot of shops out there that think they are wizards in the A/C arena but really do not know anyhting more than how to charge a system. Go with one you trust.
Again thanks for the question and good luck. Sorry I couldn't be of more help.
