A/C won't switch from floor to vents

[gamitchss1]

My 98 Grand Prix GT is having a problem with the vents. It won't switch from floor to the vents. Is there a door in the A/C/Heater unit? Is it electrically controlled or vacum controlled?

Thanks,
GM

[BNaylor]

Welcome to AF.

The actuators are both vacuum and electrical. Check the accessory vacuum line from the back of the upper intake manifold along the firewall and where it loops by the battery/main fuse box and into the main wiring harness that goes into the firewall and HVAC. Low or no vacuum will cause airflow and vent problems.

[gamitchss1]

Thanks for the reply. I found the vacum line on the back of the manifold, followed it to the a fitting behind the battery. The fitting is cracked. There is one line atached. I think there is a second line supposed to be attached to the fitting. I'll have to pull the battery to find the second vacum line. And make a trip to the Pontiac place for a new fitting.

Thanks for the advice.

GM

[richtazz]

You could just buy a short piece of rubber vacuum hose that fits snugly over the hard plastic line and repair it that way. I would bet the GM factory parts are $$$.

[gamitchss1]

I'll probably do that. I'll make a trip to NAPA for some vacuum hose and a T.

Thanks,
GM