Principles of Operation
WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel dimmer switch is an integral part of the headlamp switch assembly and allows the brightness level of the backlight to be adjusted dependent on the customer's preferences. When the headlamp switch is in the PARK or ON position, the intensity of the backlight can be adjusted by rotating the instrument panel dimmer switch right or left.
Battery voltage is supplied to the headlamp switch through the central junction box (CJB). From the instrument panel dimmer switch, variable voltage is sent back through the CJB to the controlled components with backlight lamps.