Ford F series Owner's Manual page 66

Combination Cargo and High-Mount
Brakelamp
The combination cargo/high-mount brakelamp is
located outside the vehicle, directly over the rear
window. Use the headlamp control switch to
turn on the cargo lamp and interior courtesy
lights.
A high-mount brakelamp feed is provided in the
taillamp wiring, in the event an aftermarket cap
is installed on the vehicle obscuring the
cargo/high-mount brakelamp on the cab. The
feed is located at the left rear of the vehicle,
behind the bumper and is marked with a white
tag "center high-mount stop lamp."
Cargo/High-mount brakelamp
Do not drive your vehicle with the
cargo/courtesy light on. Showing a white
light to the rear while driving on public
roads is illegal in some places.
RWARNING
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