Grand Cherokee 2WD V8-4.7L VIN N (2000)
Headlamp Switch: Description and Operation
HEADLAMP SWITCH
The headlamp switch is integral to the exterior lighting switch, which is part of the left (lighting) multi-function switch unit located on the left side
of the steering column. A knob on the end of the left control stalk controls all of the exterior lighting functions. The exterior lighting switch is hard
wired to the Body Control Module (BCM) through the instrument wire harness.
The exterior lighting switch uses a hard wired 5 volt reference circuit from the BCM, resistor multiplexing and a hard wired switch output circuit
in the instrument panel harness to provide the BCM with a 0-5 volt signal that indicates the status of all the exterior lighting switch settings. The
headlamp switch cannot be repaired. It must be replaced.
The headlamp switch is integral to the exterior lighting switch, which is part of the left (lighting) multi-function switch unit located on the left side
of the steering column. A knob on the end of the left multi-function switch control stalk controls all of the exterior lighting switch functions. The
exterior lighting switch is hard wired to the Body Control Module (BCM) through the instrument panel wire harness.
The exterior lighting switch cannot be adjusted or repaired and, if faulty or damaged, the entire left multi-function switch unit must be replaced.
The exterior lighting switch uses a hard wired five volt reference circuit from the BCM, resistor multiplexing and a hard wired switch output
circuit in the instrument panel wire harness to provide the BCM with a zero to five volt signal that indicates the status of all of the exterior lighting
switch settings. The BCM then uses control outputs to energize the headlamp and park lamp relays that activate the exterior lighting circuits.
The BCM monitors the exterior lighting switch status, then sends the proper switch status messages to other electronic modules over the
Programmable Communications Interface (PCI) data bus network. The exterior lighting switch status is also used by the BCM as an input for
chime warning system operation.
