Remove all jewelry such as rings, dog tags, bracelets, etc. If jewelry or tools contact positive electrical
circuits, a direct short may result. Damage to equipment, injury, or death to personnel may occur.
(1) Remove rear junction box cover.
(2) Connect positive (+) multimeter lead
to rear junction box, terminal wire
(3) Connect negative (--) multimeter lead
to a known good ground.
(4) While assistant fully applies brake
pedal, observe multimeter
(a) If 22 to 28 vdc are not present,
release brake pedal and
repair wire 1003C (see schematic,
Fig FO-1.1) or replace trailer main
wire harness (Para 4--30.1).
(b) If 22 to 28 vdc are present,
release brake pedal and repair
wire 1003C/22 (see schematic,
Fig FO-1.1) or replace composite
light harness (Para 4--30.1).
(6) Install rear junction box cover.