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 1225 of 1313
FIVE INDICATOR LIGHTS FLASHING - Continued
STEP
11.
IS THERE NO CONTINUITY BETWEEN PRESSURE SWITCH PINS A AND B WHEN AIR SYSTEM IS
BELOW OPERATING PRESSURE?
a.
Refer to point to point schematics.
T0422DAA
PRESSURE
TRANSDUCER
Figure 11.
Pressure Transducer.
b.
Connect multimeter red lead to to pressure switch at pin A.
c.
Connect multimeter black lead to pressure switch at pin B.
d.
Shut off air supply or engine.
e.
Drain secondary tank until air pressure gauge indicates less than 80 psi.
.
f.
Pressure switch should open.
g.
Meter reading should be greater than 90 ohms.
CONDITION/INDICATION
IS THERE NO CONTINUITY BETWEEN PRESSURE SWITCH PINS A AND B WHEN AIR SYSTEM IS BELOW
OPERATING PRESSURE?
DECISION
YES - Go to Step (12).
NO - Replace pressure switch (Volume 2, WP
0324). Go to Step (17) to verify problem is solved.
TM 9-2320-272-23-1
0146
0146-12
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