HVAC mode knob not working [Archive] - GrandAmGT.com Forum


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06-29-2005, 12:17 PM
Anybody have a fix for the mode knob on the climate controls. I've read theads on the fan speed resistor issue, but my problem is that the air is stuck in the position where the air blow at the top and the floor. The fan speeds are fine.

06-29-2005, 06:01 PM
Your vacuum line that goes to the HVAC module (head unit) doesn't have any vacuum anymore. Either that or your mode switch is messed up.

06-30-2005, 11:53 AM
Where is the Headunit located?

06-30-2005, 12:40 PM
sounds like a vaccum hose off. They are on the back of the HVAC controls.

07-03-2005, 10:58 AM
The head unit is the unit with the 3 knobs.

07-03-2005, 07:16 PM
Thanks for the replies. The problem was the vacuum hose under the hood on the left side of the upper intake. It was a thin hard plastic hose that broke last year and I retaped with electrical tape. The heat loosend the tape and made it come loose. At the time I didn't know what it was and it did not affect the cars drivablity so I left it loose. I alway noticed it had a suction and figured I'd connect it with a rubber hose and see if I'd get lucky. It did and everything works fine. Thanks