On my '69 Cutlass S convertible the door locks are apparently vacuum operated. (not familiar with this type of setup). When tracing the vacuum lines there are 3 that go to each lock. However, none of them work. I don't have the vacuum canister that looks like a coffee can and wondering if this might be the cause?

 

Chapter six in the Fisher Body Manual provides all the details and plumbing.


Each vacuum actuator in the door has two hoses, one for LOCK and one for UNLOCK. The switches have three hoses, one for LOCK, one for UNLOCK, and one for vacuum source.



The trick is that the switches don't operate the actuators directly, they operate a remote vacuum valve. Think of this like an electrical relay - the switch operates the remote valve, and the remote valve directs the vacuum from the reservoir to the actuators.



If you don't have a reservoir, then I suspect you don't have vacuum source to the remote valve. That's like not having a power wire to an electric circuit.

 

https://phscollectorcarworld.blogspo.../?view=classic

There's a couple pages in there about these. The CSM accessories section may have this system. Missing the tank will not make the system inoperable, it will just make it require the engine to be running to work. I believe the basic setup is that vacuum goes to this massive thing under the dash, and it routes vacuum one way or the other to the door actuators. The switches in the doors also have vacuum lines and they run vacuum from the source to whichever input you declare via the switch on the big thing, which appears to be a massive vacuum relay.

 

Joe beat me to it.