Table 4-2. Organizational Troubleshooting (Con't).
TEST OR INSPECTION
Connect intervehicular cable assembly to towing vehicle (para 2-10). Check voltage as follows for
each inoperative lamp until problem is isolated. Attach red multimeter lead to intervehicular cable
assembly socket (4). Attach black multimeter lead to ground (5). Turn on light switch or apply
If no voltage is present, repair or replace intervehicular cable assembly (para 4-23 or 4-24).
Attach red multimeter lead to wiring harness socket (2) and black lead to ground (5). Turn on light
switch or apply brakes.
Remove lamp (3) from socket. Attach red multimeter lead to lamp socket and black lead to ground
(5). Turn on light switch or apply brakes.
If no voltage is present, repair or replace wiring harness (para 4-25 or 4-26) or composite light
DIM OR FLICKERING LAMPS.
Check for burned out or defective lamps.
Check wiring for loose connections, broken wires, and short circuits.
Tighten loose connections. Repair short circuits. Repair or replace broken wires (para 4-23,
Check wire 90A (ground lead) for continuity. Disconnect intervehicular cable assembly from towing
vehicle. Attach multimeter red lead to pin D1 (1) and black lead to terminal end. If continuity is not
present, attach ground lead terminal and check again.
HANDBRAKES WILL NOT HOLD TRAILER.