defroster not shutting off??

[Chris6050]

My dad has a 90 GT vert and he's having a problem with his defroster and heating. Even if the A/C dial is in the off position, the defroster is still on. You can move it to vent, A/C, defrost, floor, ect.. and it still stays on. Anyone know what could cause this? Also his heat doesn't work very well at all. It only seems to blow out cool air? Thanks for the help.

-Chris

 

[89MustangGX]

Sounds like the vacuum line for one of the canisters in the dash may have come off...look up under the dash on the driver's side for a yellow vacuum tube and a gold canister. They need to be connected...