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 380 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-11.

TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

81.

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

4

Check for voltage at 12-volts dc

Go to step 5

Repair circuit

circuit 23F-TN terminal

nominal

23F-TN

and/or

of relay RY-5

23Z-TN (para

relay RY-5,

relay connec-

tor, and cir-

cuit breaker

bracket (para

3-112 and

3-114).

NOTE

With positive lead on circuit 23F-TN, check ground with negative lead for steps 5 thru 12.

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-5, relay

connector, and

circuit breaker

bracket (para

3-112 and

3-114).

2-254