Dear Car Talk:
I have a 2008 Chrysler Town and Country with the 3.8-liter V-6 engine. I get heat when I want outside air or air conditioning. I have brought the car to Chrysler twice, and they say the system is working properly, and they properly charged me for telling me that both times.
But I still get the heat. I looked for a valve that could be stuck open and be causing this, but I can see none in the system. I thought of putting one in, but then I saw that all the heater lines are actually metal, and integrating a valve would be difficult. There has to be something that segregates the hot from the cold and ambient air systems. I always enjoy your column, and hope you can help me. Thank you.
Well, the first thing I'd do is when the dealer charges you for telling you that it's working properly, say, "No, actually, it's not." And then have him sit in the car so he can feel the heat.
My guess is that you have a blend door that not's closing. The dealer should have been able to figure that out.
In the majority of cars now, there's no heater control valve to stop the warm engine coolant from circulating through the heater core behind your dashboard. If you have climate control in your car, you definitely don't have a heater control valve.
There are just flaps inside the ducts, called "blend doors," operated by vacuum motors, that open and close to allow heat or stop heat from coming through the vents into the passenger compartment. And it sounds like one of your blend door motors is no longer working and that door is stuck in the open position.
Unfortunately, if you really want to fix it, you'll probably have to take apart the dashboard to get to it. Which makes it even more surprising that your dealer didn't home in on this: He can easily make a boat payment on this kind of repair.
So, at this point, I'd recommend that you try another dealer or an independent mechanic. There's a database of mechanics personally recommended by other readers and listeners of ours that you can search by ZIP code. You can find it at www.mechanicsfiles.com.
And if the price is too high for you, see if Costco is still selling that 128-pack of Bermuda shorts. Best of luck.