5-10. WIRING HARNESS MAINTENANCE
a. Front Wiring Harness.
This task covers testing and repair of front wiring
h a r n e s s.
TOOLS: No. 1 Common Organizational Maintenance Tool Kit
Combination box and open end wrench set
Socket wrench set, 3/8 inch drive
E l e c t r i c a l r e p a i r t o o l k it
Soldering gun, 25 watts
MATERIALS/PARTS: Clean cloths (Appendix C, item 1)
Insulation tape (Appendix C, item 5)
Solder (Appendix C, item 16)
Electrical cleaner (Appendix C, item 19)
Electrical sealer (Appendix C, item 20)
PRELIMINARY PROCEDURE: Battery ground cable disconnected (page 5-148).
TESTING (SHEET 1 OF 2)
T e s t i n g c o n s i s t s o f s t a r t i n g t h e e n g i n e a n d o p e r a t i n g a l l f r o n t w i r i ng
harness circuits as shown in figure FO-3. The wiring harness is okay if
a l l c i r c u i t s f u n c t i o n n o r m a l l y . I f n e c e s s a r y , y o u m a y t e s t i n d i v i d u al
w i r e s f o r c o n t i n u i t y b y e n e r g i z i n g t h e c o r r e s p o n d i n g c i r c u i t s h o w n in
figure FO-3 and checking for voltage using multimeter or test light. To
test for shorted or grounded wire, you must disconnect both ends of wire
under test as follows.
(1) Tag front wiring harness connectors and disconnect as follows:
Unplug block-type connectors from ignition switch, blackout lights
wiring harness, and cab lower wiring harness by grasping with fingers
and pulling firmly.
Unplug connectors from vehicle lights switch and hydraulic control
valve by turning connector nut counterclockwise and pulling firmly.
Unplug connectors from instrument cluster pins (page 5-40).
Disconnect friction-type spade and bullet terminals by grasping termi-
nals with fingers and pulling firmly.
Disconnect lug terminals by loosening and removing attaching nuts or
( f )
Remove resistors by grasping fuseholder halves with fingers, pushing
together, twisting counterclockwise, and pulling apart .