TM-9-2320-285-24-1

TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1

TECHNICAL MANUAL; ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

OCTOBER 1985

TM-9-2320-285-24-1 - Page 933 of 987

TM 9-2320-285-24-1

2-84.

HOURMETER TROUBLESHOOTING

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1.

HOURMETER INOPERATIVE

Step 1.

Raise instrument panel (para 2-26g(1)).

Unplug electrical leads from hourmeter terminals (para 2-88).

Using 12 volt battery and jumper cables,

apply 12Vdc across

hourmeter terminals (be sure to use correct polarity).

Record hourmeter display time to nearest 1/10 hour; watch hourmeter

for six minutes.

a.

If hourmeter display does not advance approximately 1/10 hour,

hourmeter is defective; replace (para 2-88).

b.

If hourmeter display advances approximately 1/10 hour,

go to

step 2 below.

Step 2.

Raise instrument panel (para 2-26g(1)).

Check hourmeter for loose or incorrect connections and broken

conductor.

a.

If connections are loose or incorrect,

tighten or correct (para

2-88).

b.

If conductor is broken,

replace (para 2-88).

2-910