josephf31 wrote:
Well the vacuum hoses look OK, although I can't find a check valve under the hood; there is a "T" on the left front fender going from the TPI vacuum source to the vacuum canister in the LF wheelwell, and to the cruise control servo.

Is there supposed to be a check valve in the lines here somewhere, if so where? and if it was missing I don't see how that would make the system get stuck in defrost?

In case I do have to replace the programmer, how tough is it? It looks pretty buried up under the dash (though I still have it all apart).

Thanks all