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 253 of 926

TM 9-2320-283-20-1

TROUBLESHOOTING.

2-11.

TROUBLESHOOTING PROCEDURES (Continued).

MALFUNCTION

INSTRUCTION

INDICATION

YES

NO

38.

WASHER LAMP AND/OR WIPER LAMP NOT WORKING.

NOTE

•

Headlamp

rheostat

switch

must

be rotated fully

clockwise when doing the following check.

•

Do steps 1 thru 5

only if wiper lamp is not working or if

both lamps are not working.

•

Do steps 3, 4, and 6 only if washer lamp is not

working.

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 wiper lamp.

3-127).

NOTE

With positive lead on circuit 29-BR, check ground with

negative lead when doing the following checks.

3.

Check for voltage at

12-volts dc

Go to step 4.

Clean and/or

ground point of

nominal.

tighten ground

circuit 99D-BK.

point connec-

4.

Check for voltage at

12-volts dc

Go to step 5

Repair circuit

circuit 99D-BK termi-

nominal.

or 6.

99D-BK (para

nal of washer lamp.

3-127).

2-128