K 3500 Truck 4WD V8-6.5L DSL Turbo VIN S (1999)
Ignition Lock: Description and Operation
All vehicles equipped with a column-mounted shift lever contain both mechanical and electrical neutral safety start systems. These systems rely on a
mechanical block as well as an electrical switch in order to prevent starting the engine in any gear other than PARK or NEUTRAL.
The mechanical block is a wedge-shaped lock bolt that is added to the ignition switch actuator rod.
In either PARK or NEUTRAL, the wedge-shaped lock bolt passes through the slots in the shift bowl and the lock bolt allows the lock cylinder to turn
and start the engine.