TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 825 of 1313
STOPLIGHT INOPERATIVE (SERVICE OR BLACKOUT) - Continued
STEP
8.
IS STOPLIGHT SWITCH OPERATING PROPERLY?
a.
Connect circuit 75 wire where battery voltage was present to stoplight switch terminal.
T0764DAA
Figure 8.
Stoplight Switch Test.
b.
Connect multimeter red lead to circuit wire 75 at stop switch. Refer to point to point schematic.
c.
Connect multimeter black lead to vehicle chassis ground.
NOTE
For stoplight circuit test, air pressure must be maintained atIS THERE CONTINUITY
ACROSS CIRCUIT WIRE 75? operating pressure and brake pedal must be depressed.
d.
Start vehicle engine and depress brake pedal.
e.
Meter reading should be less than 200 ohms.
CONDITION/INDICATION
IS STOPLIGHT SWITCH OPERATING PROPERLY?
DECISION
NO - Replace defective stoplight switch (Volume 2, WP
0335). Go to Step (12) to verify problem is solved.
YES - Go to Step (9).
TM 9-2320-272-23-1
0095
0095-8
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