Key In Ignition Reminder

The radio receives a class 2 message from the Instrument Panel Module (IPM) in order to activate a continuous, medium rate chime. The key-in-ignition audible warning is activated when the following occurs:
^ The key is in the ignition, grounding the key in ignition switch signal circuit.
The IPM monitors the key in ignition switch signal circuit.
^ The IPM receives a class 2 message from the DDM that the driver door is open. The signal circuit is low.