Principles of Operation

WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

The instrument cluster controls the following warnings and chimes:

driver safety belt not fastened warning chime (warning times out)
key-in-ignition warning (repetitive chime)
headlamp-on warning (repetitive chime)
door ajar warning (repetitive chime)
safety belt warning chime (repetitive chime)
belt minder warning chime (repetitive chime after a delay and the safety belt chime has completed)

The safety belt warning chime warns that the driver safety belt is not fastened. The safety belt warning chime sounds when the driver safety belt is not fastened and the ignition switch is turned from the OFF/LOCK or ACC positions to the RUN or START position.

The safety belt warning chime stops sounding when the safety belt is fastened, when the ignition switch is turned from the RUN or START position to the OFF/LOCK or ACC position, or when the chime has sounded for approximately 6 seconds.

The safety belt warning chime inputs are:

the ignition switch START position, with voltage applied on START circuit 489 (PK/BK).
the ignition switch RUN position, with voltage applied on RUN circuit 295 (LB/PK).
the driver safety belt switch data communicated by the restraint control module (RCM) to the instrument cluster on circuit 1390 (DB).

The safety belt warning indicator, along with the chime, warns that the safety belt is not fastened. The safety belt warning indicator is illuminated when the safety belt is not fastened and the ignition switch is turned from the OFF/LOCK or ACC position to the RUN or START position.

The safety belt warning indicator turns off when the safety belt is fastened, the ignition switch is moved from the RUN or START position to the OFF/LOCK or ACC position, or if the indicator is illuminated for approximately 6 seconds.

The safety belt warning indicator inputs are:

the ignition switch START position, with voltage applied on START circuit 489 (PK/BK).
the ignition switch RUN position, with voltage applied on RUN circuit 295 (LB/PK).
the driver safety belt switch data communicated by the RCM to the instrument cluster on circuit 1390 (DB).

NOTE: The belt minder is configurable. For additional information, refer to MODULE CONFIGURATION . To configure without using a diagnostic tool, refer to SAFETY BELT MINDER DEACTIVATING/ACTIVATING .

The belt minder feature supplements the current safety belt warning function. The belt minder is enabled after the current safety belt warning is complete. The belt minder reminds the driver that the driver safety belt is unbuckled by intermittently sounding a chime and illuminating the safety belt warning indicator in the instrument cluster. While activated, the belt minder alternates the chime and indicator from on for 6 seconds to off for 30 seconds.

The door ajar warning chime warns that a door is not fully closed. The chime sounds when any door or the liftgate becomes ajar while the ignition switch is in the RUN position.

The door ajar warning indicator warns that a door is not fully closed. The door ajar warning indicator illuminates when any door or the liftgate initially becomes ajar while the ignition switch is in the RUN or START position.

The door ajar warning indicator turns off when all doors and the liftgate are closed, or the ignition switch is turned to the OFF/LOCK or ACC position.

The door ajar warning indicator/chime inputs are:

the ignition switch START position, with voltage applied on START circuit 489 (PK/BK).
the ignition switch RUN position, with voltage applied on RUN circuit 295 (LB/PK).
the door ajar data communicated by the vehicle security module to the instrument cluster on the UBP communication circuit 693 (OG).

The key-in-ignition warning chime warns that the key is still in the ignition lock cylinder when the driver door is ajar. The key-in-ignition warning chime sounds when the driver door is ajar, the ignition switch is in the OFF/LOCK or ACC position, and the key is in the ignition lock cylinder.

The key-in-ignition warning chime stops sounding when the driver door is closed, the key is removed from the ignition lock cylinder, or the ignition switch is turned to the RUN position.

The key-in-ignition warning chime inputs are:

the ignition switch START position, with no voltage on START circuit 489 (PK/BK).
the ignition switch RUN position, with no voltage on RUN circuit 295 (LB/PK).
the key-in-ignition switch circuit 1414 (LG/VT), with voltage applied with the key in the ignition.

The headlamp on warning chime warns that the headlamps are on when the driver door is ajar and the key is removed from the ignition. The headlamps on warning chime sounds if the driver door is ajar, the headlamp switch is in the PARK or HEAD position, and the ignition switch is in the OFF/LOCK position with the key out.

The headlamp on warning chime stops sounding when any one of the above conditions are removed.

The headlamp on warning chime inputs are:

the ignition switch in the START position, with no voltage on the START circuit 489 (PK/BK).
the ignition switch the RUN position, with no voltage on the RUN circuit 295 (LB/PK).
the key in the ignition switch circuit 1414 (LG/VT), with no voltage applied with the key removed from the ignition.
voltage applied on the instrument illumination circuit 235 (RD/BK).