Commander 4WD V8-4.7L VIN N (2006)
Headlamp Motor: Description and Operation
HEADLAMP LEVELING MOTOR
DESCRIPTION
The headlamp leveling motor is located on the rear upper surface of each front lamp unit on models equipped with the headlamp leveling system, which
is available only in certain markets where it is required equipment. The motor is encased within a molded plastic housing and is secured by an integral
wedge-type mounting boss to a keyed flange on the back of the front lamp unit housing. A rubber seal around the circumference of the mounting boss
seals the motor to the lamp housing.
The outside of the motor housing features an integral molded connector on its rearward surface, a hex-headed adjusting screw extends from the top of the
housing, and a plastic pushrod with a ball formation on its free end extends from the motor mounting boss. Within the motor housing is a 12-volt Direct
Current (DC) servo motor, an electronic controller board that includes the motor logic circuits, and an integral screw-drive transmission. The headlamp
leveling motor is connected to the vehicle electrical system through a dedicated take out and connector of the front lamp unit wire harness.
The headlamp leveling motor is serviced as a unit with the front lamp unit. The motor cannot be repaired and, if faulty or damaged, the entire front lamp
unit must be replaced.
OPERATION
The controller board and logic circuitry of the headlamp leveling motor control motor operation based upon a voltage signal input received from the
resistor multiplexed headlamp leveling switch in the upper switch pod on the instrument panel. When the motor is energized it will extend or retract the
motor pushrod through the integral screw-drive transmission. The ball on the end of the pushrod is snapped into a socket on the back of the reflector
within the front lamp unit housing, which will cause the reflector to move as the pushrod is extended or retracted, changing the angle at which the light is
projected from the headlamp low and high beam bulbs.
The headlamp leveling motors and switch have a path to ground at all times. The headlamp leveling components operate on battery voltage received
through the fused park lamp relay output circuit so that the system will only operate when the exterior lighting is turned On.
Because of active electronic elements within the headlamp leveling motor, it cannot be tested using conventional diagnostic tools and procedures. If the
headlamp leveling system is believed to be faulty, the headlamp leveling circuits and the leveling switch must be tested before considering motor
replacement.
