Principles of Operation

WARNING: This page is about a different car, the 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

When the vehicle's ignition key is in the RUN position voltage is supplied to the upfitter relay control circuit. The upfitter relay closes and voltage is supplied to the upfitter relay box. The upfitter switch assembly receives voltage through the upfitter relay box fuse 701 (5A) and then distributes voltage to the 4 circuit control switches. When a control switch is closed it supplies voltage to 1 of the 4 upfitter relays in the upfitter relay box, closing that relay. Voltage is supplied to the switched side of the upfitter relay circuits from the central junction box (CJB). When the relay closes, voltage is supplied through the relay to the output circuits (blunt cut ends) located under the LH side of the instrument panel. The output circuits (blunt cut ends) supply voltage to the installed accessories connected to the upfitter relay box.