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 971 of 1313
HEATER WILL NOT OPERATE IN LOW OR HIGH POSITION - Continued
STEP
2.
IS HEATER SWITCH IN GOOD OPERATING CONDITION?
a.
Check for proper voltage supply from circuit 400 wire terminal on heater switch.
b.
Place battery switch to OFF position.
T0134DAA
400
5C
569B
Figure 2.
Heater Switch Wiring.
c.
Disconnect circuit 400 wire from heater switch.
d.
Place battery switch to ON position.
e.
Place heater switch to HIGH speed position.
f.
Connect multimeter red lead to the circuit 400 wire terminal at the heater switch. Refer to point to point
schematics.
g.
Connect multimeter black lead to vehicle chassis ground.
NOTE
If voltage is not present, heater switch motor is faulty.
h.
Meter reading should be greater than 18 VDC.
TM 9-2320-272-23-1
0116
0116-4
Back to Top
