NEUTRAL safety switch

[flrboard]

Does anyone have a a detailed diagram of what this switch connects to?
My 1984 720 automatic starts fine and idles fine after installing a Weber carb. But when I shift to any gear the engine quits.
I can start in neutral or park but shifting out of either kills the motor.
Any ideas on how the shift lever can turn off the motor?

[flrboard]

just to report on today's discoveries.
I have stopped chasing electrical phantoms and have begun to focus on the vacuum operated devices.
Having re introduced them into the workings of the engine , I find that now the engine does NOT die when the gear selector is moved from park.
This is an advance in two directions, The motor is still running and I can turn away from the electrical hypothesis.
This leaves me in the realm of vacuum operated controllers. Too bad.
Only some of them make appearances in my Haynes repair book.
None of them are labeled except with very old part numbers...no functional definitions.

The truck will start and run up the street very nicely..unless I floor the accelerator.
Asking for rapid acceleration produces an immediate slow down accompanied by a sound like a potato has been shoved into the exhaust. letting up on the accelerator restores smooth quiet power.

Good thing the speed limit is 25mph around here.