Turbo 350C Lockup Wiring

[dhill3443]

Check the Attachment for wiring details. The Switch on the passenger side of the transmission is a pressure switch which turns power on to the vacuum switch that has two vacuum lines. This switch cuts on in third gear to change vacuum advance on the distributor. The orange wire coming from the lockup connector feeds the pressure switch the voltage to which feeds the vacuum switch. Unless your using the electronic spark control with vacuum advance on some models, the pressure and vacuum switch are not needed. If your using a vacuum advance distributor reroute the vacuum advance to manifold vacuum and do away with the vacuum controled switch. This pressure switch has nothing to do with lockup on the converter. The only wires needed is the blue wire which comes from a power source fed off the ACC fuse panel which is (brown w/ white), through a brake switch (which becomes a blue wire), through a vacuum controlled switch mounted above the brake master cylinder and booster then down to the lockup connector on the drivers side of the transmission. You can put a toggle switch in with power to bypass the vacuum switch if full lockup is needed in a performance type situation but vacuum controled lets the motor do the work. Also on the electronic spark controlled distributors you can disconnect the electronic spark control and place a jumper to cross number 1 and 3 to allow the engine to start and run and use the vacuum advance to control timing. This information comes from the 35 year experience of the service manager and a long time Chevy mechanic at the dealership. Hope this helps. Thanks to all for those that gave me the support on here.
By the way, give credit to krue and bill for the diagram, I just redesigned it for my model which is a 1985 C10, 305/th350C. Thanks everyone.