Ignition Key Interlock

On vehicles equipped with interlock safety feature vehicle must be in park and transfer case in high or low gear before key can be removed from ignition. If gear selector or transfer were out of gear, key must be cycled before removal.

If vehicle is not in park, voltage from fuse B2 is applied to ignition Key Switch and Solenoid (X177) through closed contacts of Transmission Range Selector Switch (Z110). When ignition switch is placed in 0 position, switch is in ignition Key Switch and Solenoid closes to energize solenoid and prevent key removal.

If transfer box is in neutral position, Interlock Relay 1 (K153) is de-energized, since relay coil is not grounded by Transfer Box Position Switch. When relay id de-energized, voltage is applied to ignition Key Switch and Solenoid (X177) through relay's switch contacts causing solenoid to energize and prevent key removal.