TM 10-3930-641-20
ELECTRICAL SYSTEMS TROUBLESHOOTING (CONT)
(Sheet 5 of 7)
PROBLEM NO. 25 (CONT)
25 b. When the TAIL/PANEL LIGHT switch is closed, current flows from fuse 3, through the switch and through a.) LHIP panel lamp to ground,
b.) through each gage lamp to ground and c.) through RHIP panel lamp to ground. Current also flows through the tail light circuit, therefore,
if only tail lights work, the problem is in the ground circuit - check cab ground first. If the tail lights and LHIP panel light works, the problem
is in the GY wire or connections between the RHIP panel light and the DK BL connector at RHIP - check for proper seating of connector first.
If only one lamp is out, check bulb and then wiring to its socket (NOTE: Gage lamps are each grounded to the case of the gage, which in turn
is grounded by way of BK wires).
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