TM 5-3805-262-20
3-11. LIGHT SYSTEMS TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
3. FRONT DRIVING LIGHTS DO NOT OPERATE.
Step 1.
Place ignition key switch in on position.
Place vehicle lights switch in SER DRIVE position.
Place flood lights switch in on position.
Front driving lights and front and rear flood lights should be on.
a. If at least one driving light is on, go to step 3 below.
b . I f b o t h d r i v i n g l i g h t s a r e o f f , and at least one flood light is
on, go to step 2 below.
c . I f a l l f l o o d l i g h t s a n d d r i v i n g l i g h t s a r e o f f , c h e c k w i r i ng
connection at vehicle lights switch connector pin M. Repair con-
nector as necessary (page 5-169). If connector is okay, remove
right instrument panel (page 5-48) and replace vehicle lights
switch (page 5-53).
Step 2. Behind right instrument panel, connect multimeter between each ter-
minal of 6 ampere circuit breaker and cab sheet metal.
Check that multimeter indicates 24 volts for both terminals.
a. If multimeter indicates 24 volts for both terminals, check
wiring connection between 6 ampere circuit breaker and driving
lights. Repair or replace wire as necessary (page 5-168).
b. If multimeter indicates zero for both terminals, check wiring
connection between 6 ampere circuit breaker and vehicle lights
switch pin M. Repair or replace wire or connector as necessary
(page 5-168).
c. If multimeter indicates 24 volts at one terminal and zero at re-
maining terminal, remove right instrument panel (page 5-48) and
replace 6 ampere circuit breaker (page 5-53).
Step 3.
Disconnect wiring harness terminal from wire lead terminal of driv-
ing light by grasping both terminals with your fingers and firmly
pulling them apart.
Connect multimeter between wiring harness terminal and chassis
frame.
Multimeter should indicate 24 volts.
a. If multimeter indicates 24 volts , replace lamp (page 5-92).
b . I f m u l t i m e t e r i n d i c a t e s z e r o, check wiring connection between
driving light wiring harness terminal and 6 ampere circuit
breaker behind right instrument panel. Repair or replace wiring
as necessary (page 5-168).
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