Have a 87 GTA with the digitial dash. A/C vacuum is different from one with manual controls and has a different vacuum setup. This unit is mounted to the heater box on the passenger panel side under the dash panel where the ECM is.

Been chasing a A/C stuck on defrost and led me to this. Mounted in original position, i get the air only coming out of defrost vents. If I unmount it and let it hang, I will get air in the cabin all day no problem. But move it back up and back to defrost.

Can anybody tell me exactly what this part is, any steps I can take to remedy this problem? Would be greatly appreciated.

 

Do you have a factory manual for the digital dash stuff? If so I could use info related to the blower motor. Motor works when I jump it.

 

Anybody have this part they'd be willing to sell?

 

It's a vacuum module, they were used with the electrically controled heater systems in the digital Thirdgens. It accepts engine vacuum and then relays it to the various vacuum Solenoids to open/close the various heater box flaps.

Since it appears to work when hanging - but not work when installed,... is it possible that mounting it is causing a "crip" in the vacuum line that feeds the module ??