See?......The vehicle year makes a difference. The earlier 123's use engine vacuum for the doors and the later models have a seperate vac unit in the trunk. At least I think.
Someone familar with the 123 may chime in here.
Anyway you need to test the vac system. You will need a mity-vac.
www.harborfreight.com has them. So does Sears. You can rent one for free from AutoZone.
Look here for vacuum diagrams:
Vacuum Diagrams
Start at the pump and work your way out. It's real simple once you get started.
Danny