I'm not exactly sure, but doesn't the 123 climate control run off vacuum? If so, your door locks and A/C are related. You definitely have a vacuum leak somehwere.
Do your lock ever operate, maybe while the engine is running? If not, then I would start under the hood, there should be one vacuum line coming from the manifold, with a check valve. This line should "T" with one leg going to a vacuum resevoir (probably in left fender) the other leg through the firewall or to a distributer block on the firewall.
Good place to start is with performing a vacuum test at the check valve, then work your way through the system. Vacuum leaks also effect engine performance.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.