Headlamp Washer System Components
The headlamp washer system consists of the following components:
Headlamp Washer System Controls
Headlamp Washer System Operation
The body control module controls the headlamp washer pump using a programmed
pulse type wash sequence. The pulse washing sequence is a wash cycle for a
programmed amount of time followed by a programmed amount of delay time to
let the water soak which is then followed by another wash cycle for a programmed
amount of time. The headlamp washer pump is controlled by the body control
module through the headlamp washer relay. The headlamp washer switch signal
circuit is supplied a 12-volt reference through a resistor then monitored
within the body control module. The headlamp washer switch is open when in
an inactive state. When the headlamp washer switch is activated the signal
circuit is closed to ground. When the headlamp washer switch signal circuit
is closed to ground the reference voltage is dropped across the resistor within
the body control module. The low voltage on the headlamp washer switch signal
circuit indicates to the body control module the switch status is active.
Battery positive voltage is supplied to the coil and switch sides of the headlamp
washer relay. When a headlamp wash request is active the body control module
energizes the headlamp washer relay by grounding the relay coil through the
headlamp washer relay control circuit. When the relay is energized battery
positive voltage to the relay switch is supplied to the washer pump control
circuit.