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.
Resistors mounted on exterior of junction box
assembly reach very high temperatures when
power is applied to circuit. Avoid touching
or contacting resistors when working in or
around junction boxes. Failure to comply
could result in injury to personnel.
(1) Disconnect 24 vdc (12 terminal) cable
from front junction box
connector MC15 or from bracket, if
(2) Set multimeter select switch to volts
(3) Connect positive (+) multimeter lead
to terminal E on trailer end connector.
(4) Connect negative (--) multimeter lead
to terminal D on trailer end connector.
(5) While assistant turns ON ENGINE
switch and turns on LIGHT switch,
(a) If 22 to 28 vdc are not present,
perform Steps (6) and (7) below
and repair 24 vdc cable
(Para 4-31) or replace 24 vdc cable
(b) If 22 to 28 vdc are present, 24 vdc
cable is OK.
(6) Turn off LIGHT switch.
(7) Turn OFF ENGINE switch.
(8) Connect 24 vdc cable to front junction
box connector MC15 or from bracket,