TM 5-3805-254-20-1
ORGANIZATIONAL TROUBLESHOOTING - CONTINUED
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
21. BOTH BACKUP LIGHTS DO NOT WORK - CONTINUED.
WARNING
Although KEY SWITCH must be on and battery ground cable connected to test electrical
circuit voltage, turn off KEY SWITCH and disconnect battery ground cable before doing
resistance tests or replacing parts. This will keep you from getting shocked and prevent
damage to parts and equipment.
NOTE
Scrape painted surfaces to bare metal before connecting test leads to ensure correct
multimeter readings.
Step 9.
Set multimeter to 20 vdc scale. Connect red test lead to terminal (1) on junction box (2) and black test
lead to ground. Have assistant rotate KEY SWITCH (3) clockwise to on position and put shift lever (4) in
reverse (R) position. Check for 11 to 13 vdc on multimeter. Have assistant put shift lever (4) in neutral
(N) position and rotate KEY SWITCH (3) counterclockwise to off position. Disconnect test leads.
a.
If multimeter does not read 11 to 13 vdc, go to step 10.
b.
If multimeter reads 11 to 13 vdc, go to step 11.
Step 10.
Disconnect batteries (page 2-424). Remove instrument panel pad (page 2-424). Using 3/8-inch box-end
wrench, unscrew and take off nut (5) and 71A wire (6). Set multimeter to ohms scale and adjust to 0
ohms. Connect red test lead to wire terminal (7) on 71A wire (6) and black test lead to terminal (8) on
circuit breaker (9). Check for 0 ohms on multimeter. Disconnect test leads.
a.
If multimeter reads no continuity, 71A wire (6) must be replaced. Notify Direct Support Maintenance.
2-150
