TM 9-2320-273-20
2-35. RELAYS AND CIRCUIT BREAKERS.
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RELAY (K1). (M915 thru M920) Normally open contacts: Provides 12-volt power to
the electric horn when energized.
RELAY (K2). (M915, M916, and M920) Normally open contacts: Provides 24-volt power
to trailer left turn signal light when energized.
RELAY (K2). (M918 and M919) Normally closed contacts: Provides 12-volt power to
the backup alarm when energized.
RELAY (K2). (M917) Normally closed contacts:
Disconnects 12-volt power from
tractor backup lights when the Operation switch is in BLACKOUT position,
RELAY (K3). (M915, M916, and M920) Normally open contacts: Provides 24-volt
power to trailer right turn signal light when energized.
RELAY (K4). (M915, M916, and M920) Normally open contacts: Provides 24-volt
power to trailer blackout stop lights when energized.
RELAY (K5). (M915, M916, and M920) Normally open contacts: Provides 24-volt
power to trailer blackout tail lights when energized.
RELAY (K6). (M915, M916, and M920) Normally open contacts: Provides 24-volt
power to trailer marker and tail lights when energized.
RELAY (K7). (M915, M916, and M920) Normally closed contacts: Disconnects
12-volt power from tractor backup lights when operation switch is in BLACKOUT
position.
RELAY (K8). (M916 and M920) Normally closed contacts: Provides 12-volt
power to work lamps when WORK LAMPS switch is ON.
ENGINE TEMPERATURE DIODE. Provides a circuit to illuminate engine temperature
indicator when engine is cranking, and prevents engagement of the starter by feedback
voltage in the event the water temperature switch closes.
CIRCUIT BREAKER (CB-9). Protects the 12-volt work lamps circuit in the M916 and
M920 vehicles.
ClRCUIT BREAKER (CB-8). Protects the 24-volt blackout stop, marker, and tail light
circuits for trailers used with the M915, M916, and M920 vehicles.
ClRCUIT BREAKER (CB-7). Protects the 24-volt left and right turn signals and
blackout tail light circuits for trailers used with the M915, M916, and M920 vehicles.
ClRCUIT BREAKER (CB-6). Protects the 12-volt engine retarder brake, instrument
gages, low air, park brake, and differential lockout circuits in the M915 thru M920
vehicles.
CIRCUIT BREAKER (CB-5). Protects the 12-volt backup lights and ether start circuits
in the M915 thru M920 vehicles.
CIRCUIT BREAKER (CB4). Protects the 12-volt heater fan motor circuit in the M915
thru M920 vehicles.
CIRCUIT BREAKER (CB-3). Protects the 12-volt cigar Iighter and dome light circuits
in the M915 thru M920 vehicles.
CIRCUIT BREAKER (CB-3). Protects the 12-volt utility outlets on the M915, M916,
and M920 vehicles.
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