Section 01-11: Glass, Frames and Mechanisms | 1996 F-150, F-250, F-350, F-Super Duty and Bronco Workshop Manual |
The heated back window switch and light (18C621) consists of a control assembly mounted to the instrument panel finish panel (044D70), and a series of grid wires bonded to the inside surface of the tailgate back window glass and system wiring.
When the heated back window switch and light is activated by the pushbutton, current is directed to the grid wires on the tailgate back window glass. The heated grid wires keep the tailgate back window glass clear of fog or ice.
The integral timer automatically turns off the heating grid after approximately 10 minutes of operation. If more than 10 minutes of use is needed, the grid can be reactivated for another 10 minutes by pushing the pushbutton to the ON position. This operation can be repeated as required.
Power for the control timer and relay coil comes from the RUN terminal of the ignition switch (11572) and from the high-current fuse panel.
The heated back window switch and light can be deactivated before automatic time out by momentarily depressing it to the OFF position, or by turning the ignition switch to the OFF position.