Okay, looks like the master switch (in the driver's door) isn't holding vacuum, so someone in the long line of POs completely disconnected the whole door system at the 3-way check (yellow) in the engine compartment... the check valve was connected to a switch over valve with an elec lead out of the bottom, looks identical to the tranny and EGR switch over valves. See Shorebilly's vacuum thread for more. Anyway, the supply to the bottom of this elec valve is missing.

So, my question is, can I just plumb into supply anywhere? I'm thinking of adding a three way split somewhere after the transmission (letter c in this diagram). Add the 3-way check valve (the yellow one), and connecting up to the two yellow lines that feed the door locks. Assuming replacing the master switch in the driver's door solves the problem in that circuit.

Will it work?

__________________
Obiwanrazzy
1985 300D 267k and hemorrhaging...