CHAPTER 2: VEHICLE MAINTENANCE INSTRUCTIONS
TM 9-2350-256-20
2-19 ELECTRICAL TROUBLESHOOTING-Continued
EXTERNAL VEHICLE WARNING HORN-Continued
WARNING
Remove all jewelry such as rings, dog tags ,
bracelets, etc. If jewelry contacts a metal
surface a direct short may result in instant
heating of tools, damage to equipment, and
injury or death to personnel.
A Remove three screws (1), three lockwashers (2),
ground lead (3), and flat washer (4), and release
main switch panel (5) from mounting brackets.
Disconnect switch panel to gage panel and
miscellaneous switches wiring harness from main
switch panel. Place red lead of multimeter on pin
N of wire 10 and black lead to ground. Turn
MASTER switch on and check for voltage. Turn
MASTER switch OFF. If voltage is present, go to
step C. If voltage is not present, go to step B.
B Reconnect switch panel to gage panel and
miscellaneous switches wiring harness to main
switch panel. Install main switch panel (5), flat
washer (4), ground lead (3), three lockwashers (2),
and three screws (1) to mounting brackets. Open air
inlet doors (TM 9-2350-256-10). Disconnect wire 48
pin A from bulkhead to master relay wiring
harness. Place red multimeter lead on pin A and
black lead to ground. Turn MASTER switch on and
check for voltage. If voltage is present,
repair/replace switch panel, radio, and bilge pump
to bulkhead wiring harness (see paragraph 6-53).
If voltage is not present, troubleshoot master relay
circuit (see paragraph 2-19, master relay fails to
operate).
2-220
