Sentry Key Immobilizer System

The Sentry key Immobilizer System (SKIS) indicator gives an indication to the vehicle operator of the status of the SKIS. This indicator is controlled by the instrument cluster electronic circuit board based upon electronic messages received by the cluster from the Sentry Key Immobilizer Module (SKIM) oner the Programmable Communications Interface (PCI) data bus. The SKIS indicator LED receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or START positions. The indicator will always be off when the ignition switch is in any position except ON or START. The LED onlu illuminates when it is switched to ground by the instrument cluster transistor. The instrument cluster will turn on the SKIS indicator for the following reasons: bulb test, SKIM lamp-on message and actuator test.

The SKIM performs a self-test each time the ignition switch is turned to the ON position to decide whether the system is in good operating condition. The SKIM then sends the proper SKIS lamp-on or lamp-off messages to the instrument cluster.`