1977 911s Sportomatic - bypass bridge switch?

[HammerESQ]

I'm in the process of getting a 1977 911s Sportomatic running again.

I've got the engine running well, but I'm having issues with the Sportomatic. The clutch isn't engaging, and all signs are pointing to the servo diaphragm. Before I undertake the process of rebuilding or replacing it I would like to verify that the transmission, torque converter, etc actually work.

I've seen references to people bypassing the 'Bridge Switch' which prevents the car from starting in anything but park or neutral, and then starting the car in gear what a foot on the brake. However I haven't actually seen anyone explain how to do this.

I've identified the switch and the pin's that have 12V when the ignition is in the run and the start position however electrical work is not my area of expertise, any advice would be awesome.

[Bob Kontak]

Use the Search "Advanced Search" function and search on keyword "Sportomatic" in the 911 Tech forum and simply read.

[HammerESQ]

Originally Posted by Bob Kontak

Use the Search "Advanced Search" function and search on keyword "Sportomatic" in the 911 Tech forum and simply read.

Bob,
Oh trust me, I have. There is tons of information, but nothing specifically about jumping the safety switch (although several have talked about it). What I did find is the below diagram. I tried jumping across wire 50 on switch 4, do I need to jump it on Switch 2 as well?

I'm not good with electrical stuff, and really want to figure out if this car will run with minimal work to the sportomatic, or if I should be looking for a 915 to swap in.

[sportoextremist]

Have you looked at or done any sort of testing on the microswitch on the shiftlever?

With the ignition on, but the car not running, if you shift in and out of gears, you should be able to hear a click from the engine bay from the switch controlling the airvalve.

[HammerESQ]

I have, with the car off and the engine running I can hear a click in the engine bay when I push the shifter up and down.

The PO of the car had a new vacuum valve installed less than 1000 miles ago (although it has been 10 years). I haven't dug into it yet, but the servo on the gearbox and the vacuum lines seem to be the two things not replaced.