QuestionI have a '97 Monte Carlo and for some reason cold air only blows out the driver's side vents and ambient air temp. out the passenger side. However, if I set the climate control to warm then both sides work. What could cause this?
AnswerDave,
Am I correct in assuming that you have dual zone climate control? If so, inside your dashboard, where the ducting meets up with the fan/evaporator/heater core assembly, there are two doors that we call blend doors. For one reason or another, your passenger side door is not opening as it should, while your driver's is working perfectly. There could be several causes for this.
Car manufacturers use one of two systems to tell these doors to open and close. One is by vaccuum line. The control head sends a signal to the vaccuum control manifold which in turn sends a vaccuum to the door actuators telling them to open or close. One of yours is not, so it could be as simple as a vaccuum hose coming loose, a door actuator gong bad, or it could be that your vaccuum control manifold itself is going out.
The other system is an electronic logic system. It works basically the same way but uses electronic signals from the control head to the door motors/actuators to open and close them. In a system that uses this type, I tend to mcoe straight the door motors themselves that typically go bad. But...
Either way, I highly recommend you take it to a reputable A/C shop or even, dare I say it... the dealer, to troubleshoot. They have the correct diagnostic equipment to make this a much easier task. And if you have ever done it, anytime you take the dashboard apart, it is a fairly in-depth repair, with ample opportunities to mess something else up in the repair of one fault.
Sorry I couldn't be of more help, but I hope I led you in the right direction. Thank you for the question and good luck.
