A/C and heater control problems

[1993MTXSHO]

Hey guys everything under my dash seems to work on except when I try to switch from floor to vent or defrost or anything nothing moves; the system is stuck on defrost. Now I know this is usually a broken BCM when it defaults to defrost (I think I am right on that at least) but I can control my blower speed w/o issues. Any ideas?

TIA

 

[Rockledge]

The system defaults to defrost when there is a large vacuum leak somewhere. You might start your troubleshooting by pulling the EATC unit and making sure the vacuum harness connector in back is secure. The black vacuum line is the source that comes from the reservoir tank and check valve; the other color lines run to various control motors.

 

[1993MTXSHO]

hmmm, I wonder if I missed a vacuum line under the dash near the glovebox while replacing the blower motor. What lines are down there that I might have missed? It looks like I connected everything, but I bet thats why it's not working. I'll have to take another look tomorrow.

 

[1993MTXSHO]

took a look, nothing looks out of place. I'm going to try to run the climate control self check Tuesday and see if that comes up with anything.