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 255 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-11.

TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

39.

HEATER LAMP NOT WORKING.

NOTE

Headlamp

rheostat

switch

must

be rotated fully

clockwise when doing the following checks.

1

Check for voltage at

12-volts dc

Go to step 2

Refer to mal-

circuit 29-BR terminal

nominal

function 44.

of headlamp switch.

2

Check for voltage at

12-volts dc

Go to step 3

Repair circuit

circuit 29-BR terminal

nominal

29-BR (para

of heater lamp

3-127).

connector.

3

Remove bulb from heater

lamp socket (para 3-87),

and go to step 4.

4

Check for voltage at

12-volts dc

Replace bulb

Clean socket

socket

nominal

(para 3-87)

and install

bulb (para 3-87).

TA 236872

2-130