Principles of Operation
PRINCIPLES OF OPERATIONDimmable backlighting
When the headlamp switch is in the park or headlamp ON position a signal is sent to the smart junction box (SJB). Voltage is supplied from the SJB to the instrument panel dimmer switch, which is an integral part of the headlamp switch. The instrument panel dimmer switch generates a variable pulse width modulated (PWM) signal that controls lamp intensity of the dimmable components and switches.
Non-dimmable backlighting
When the accessory relay is energized, voltage is supplied to the door lock switches and the master window switch, turning on switch illumination. If the master window switch is in the windows UNLOCK position, voltage is supplied through the master window switch to the passenger window switch, RH rear window switch and the LH rear window switch allowing the windows to operate and illuminating each switch. If the master window switch is in the windows LOCK position, the circuit is opened preventing illumination of the passenger window switch, and both rear window switches.