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 359 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-11.

TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

79.

BOTH 24-VOLT TRAILER TAILLAMPS NOT WORKING (Continued).

NOTE

With positive lead on circuit 30P-BR, check ground with

negative lead for step 5 thru 13.

5.

Check for voltage at

12-volts dc

Go to step 6.

Clean and

circuit 99Z-BK ground

nominal.

tighten ground

point.

connection.

Install relay

RY-6, relay

connector, and

circuit breaker

bracket (para

3-112 and

3-114).

6.

Remove relay RY-2 (para

3-112), and go to step

7.

7.

Check for voltage at

12-volts dc

Install relay

Repair circuit

circuit 99Z-BK terminal

nominal.

RY-2, and go

99Z-BK (para

of relay RY-2.

to step 8.

3-127).

Install

relays RY-3 and

RY-6, relay

connector, and

circuit breaker

bracket (para

3-112 and

3-114).

2-234