Selector Lever position sensor - starting interlock switch

On cars with automatic transmission, the starting interlock switch (77) is integrated with the selector lever position sensor.

The switch (77) pins 1 and 5 are used to control stater relay.

Switch Pin 1 in supplied with B+ is fed Via the starter relay to TWICE, which grounds the input if the criteria have been fulfilled (correct key).

In all other gear position the switch is open, i.e. the starter relay is not supplied with current.

Fig 1: Identifying Selector Lever Position Sensor - Starting Interlock Switch

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Selector Lever Position Sensor - Starting Interlock Switch - Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.