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 195 of 987

TM 9-2320-285-24-1

2-19.

INSTRUMENT PANEL TROUBLESHOOTING

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1.

WATER LEVEL WARNING LIGHT AND BELL NOT OPERATING PROPERLY

Step 1.

Disconnect oil pressure sensor electrical lead (para 2-32a).

With engine stopped, turn key switch to on position.

WATER LEVEL warning lamp should light and warning bell should sound.

a.

If lamp does not light, go to step 2 below.

b.

If bell does not sound, go to step 3 below.

c.

If lamp lights, bell sounds, and OIL PRESSURE or WATER TEMP warning lamps light, go to

step 4 below.

Step 2.

Check for continuity of WATER LEVEL warning light bulb.

a.

If bulb is defective, replace (para 2-26b(4)).

b.

If bulb is not defective, repair socket and wiring as required (para 2-26b(4)).

Step 3.

Disconnect warning bell electrical leads (para 2-26c(1)).

Connect 12 Vdc power source to bell.

Bell should sound.

a.

If bell does not sound, replace (para 2-26c(1)).

b.

If bell sounds, go to step 4 below.

Step 4.

Check continuity of diodes (para 2-35f) and brown/red electrical lead connecting diodes and bell.

a.

If correct continuity is not obtained, replace diodes (para 2-35f) or repair wiring (para 2-35c(2)).

b.

If correct continuity is obtained, go to step 5 below.

Step 5.

With engine stopped, turn key switch to on position.

Disconnect oil pressure sensor electrical lead (para 2-32a).

Use a voltmeter to check for 12 Vdc at water level sensor blue/brown electrical lead.

a.

If voltmeter indicates 12 Vdc, repair or replace electrical lead (para 2-32a).

b.

If voltmeter indicates zero, go to step 6 below.

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