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.
Steps 4, 5, and 6 are typical for both backup light sockets.
Step 4.
Check each stoplight/taillight assembly (1) for looseness.
a.
If stoplight/taillight assembly (1) is loose, tighten three nuts (2) using 7/16-inch box-end wrench.
b.
If stoplight/taillight assembly (1) is not loose, go to step 5.
Step 5.
Using number one cross-tip screwdriver, unscrew and take out four screws (3) and lens (4). Push backup
lamp (5) in and turn counterclockwise and take out. Set multimeter to ohms scale and adjust to 0 ohms.
Connect red test lead to contact (6) and black test lead to metal base (7). Check for 0 ohms on
multimeter. Disconnect test leads.
a.
If multimeter does not read 0 ohms, replace backup lamp (5). Put backup lamp (5) into socket (8),
alining pins with slots. Push in, turn clockwise and release. Put lens (4) into stoplight/ taillight
assembly (1). Screw in four screws (3) and tighten using number one cross-tip screwdriver.
b.
If multimeter reads 0 ohms, go to step 6.
Step 6.
Check socket (8) for corrosion or rusted out condition.
2-144
