: New Engine...climate control issues.

11-23-07, 02:15 PM
We recently put in a 98 Deville engine in my STS. Only a few minor glitches I am still working out. One of the more frustrating ones has been the climate control. Here is the problem.

The controls themselves are working. I can set the fan to run window, vents, floor, etc. But the only problem is, the actuator or whatever controls where the air is directed, will not move. So its always stuck on defrost.

I think all this stuff runs on vac tubes right? I dont even know where to start looking. Also, my parking brake doesnt want to dissengage on its own.

any help is appreciated :bouncy:

11-23-07, 06:03 PM
Also, my parking brake doesn't want to dissengage on its own.
Start by checking the parking brake vacuum diaphragm to be sure it will hold a vacuum. If it leaks, the release will not work and the HVAC system will default to defrost. If that is OK, check the vacuum supply line where it enters the passenger cabin at the firewall on the passenger side to be sure it has vacuum. If not, follow it back to locate where it is disconnected. I think it runs to a vacuum reservoir under the battery then to a manifold supply port.

Mark C
11-23-07, 06:29 PM
Did you hook the vacuum line that runs through the penetration on the passenger side of the firewall (at least on an 97 STS). Its the plate just inboard of the hood hinge. It has wiring for a set of HVAC relays and theres a vacuum tube buried in the bundle. Its the main vacuum supply for everything under the dash.