TM-9-2320-283-20-1

TRUCK TRACTOR, LINE HAUL, 50,000 GVWR, 6X4, M915A1

TECHNICAL MANUAL; ORGANIZATIONAL MAINTENANCE PART 1 OF 3

DECEMBER 1983

TM-9-2320-283-20-1 - Page 398 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-11. TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

83.

PERSONNEL HEATER FAN MOTOR NOT WORKING.

NOTE

•

Make sure ignition switch is in ON position and heater fan switch is set

at speed being tested when doing the following checks.

•

If any speed is working, begin with step 3.

1.

Remove circuit breaker

bracket far enough to

access circuit breaker

CB-4 (para 3-114), and

go to step 2.

2

Check for voltage at

12-volts dc

Install circuit

Reset circuit

circuit 76-DB terminal

nominal.

breaker panel

breaker CB-4

of circuit breaker

(para 3-114),

and/or trouble-

CB-4.

and go to step

shoot CB-4 cir-

3.

cuit.

(Refer

to malfunction

33).

3.

Check for voltage at

12-volts dc

Go to step 4.

Repair circuit

circuit 76-DB terminal

nominal.

76-DB (para

of heater fan switch.

3-127).

4.

Check for voltage at

12-volts dc

Replace person-

Replace heater

LOW, MED, and HIGH

nominal.

nel heater

fan switch

terminals of heater fan

motor (para

(para 3-81).

switch.

3-299).

2-272