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 297 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-11.

TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

56.

BOTH STOPLAMPS NOT WORKING (Continued).

NOTE

Blackout toggle switch must be set to NORMAL position, air system pressurized

to 105 psi, and brake pedal depressed by assistant when doing the following

checks.

7.

Check for voltage at

12-volts dc

Go to step 8.

Replace stop-

circuit 25B-YL ter-

nominal.

lamp switch

minal of stoplamp

(para 3-183).

switch.

8.

Check for voltage at

12-volts dc

Connect cir-

Repair circuit

circuit 25B-YL ter-

nominal.

cult 25B-LY

25B-YL (para

minal of connector.

to 25C-LY,

3-127).

and go to

step 9.

9.

Check for voltage at

12-volts dc

Go to step 10.

Repair circuit

circuit 25C-YL ter-

nominal.

25C-YL (para

minal of blackout

3-127).

toggle switch.

10.

Check for voltage at

12-volts dc

Go to step 11.

Replace black-

circuit 25D-RD ter-

nominal.

out toggle

minal of blackout

switch (para

toggle switch.

3-79).

2-172