Is there a vaccum selector for the heater controls on 2002 supercrew lariats? The zone selector keeps defaulting to defrost when I apply throttle. When sitting still, it stays where it is supposed to. I am freezing my feet off because the heater will only blow defrost while driving. It behaves like a problem I once had with an old car I had with a bad vaccum selector valve. If it has one, is it possible to get at it? I would like to buy a proper service manual for this truck so I can look this stuff up. Anyone have any suggestions. Thanks for any replies. d_t

 

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Steve