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 313 of 926

TM 9-2320-283-20-1

2-11.

TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

61.

BOTH BLACKOUT MARKER LAMPS NOT WORKING.

NOTE

Headlamp switch must be in ON position and blackout

toggle switch set to BLACKOUT position when doing the

following checks.

1

Check for voltage at

12-volts dc

Go to step 2

Refer to mal-

circuit 30-OR terminal

nominal

function 44.

of headlamp switch.

2

Check for voltage at

12-volts dc

Go to step 3

Repair circuit

circuit 30-OR terminal

nominal

30-OR (para

of blackout toggle

3-127).

switch.

3

Check for voltage at

12-volts dc

Go to step 4

Replace black-

circuit 23Z-TN ter-

nominal

out toggle

minal of blackout

switch (para

toggle switch

3-79).

4

Disconnect circuit

23-TN from 23A-TN at

connector, and go to

step 5.

5

Check for voltage at

12-volts dc

Repair circuit

Repair circuit

circuit 23-TN terminal

nominal

23A-TN (para

23-TN and/or

of connector

3-127)

23Z-TN (para

3-127)

62 ONE BLACKOUT MARKER LAMP NOT WORKING.

NOTE

-Headlamp switch must be in ON position and blackout

toggle switch set to BLACKOUT position when doing the

following checks.

2-188