TM-9-2320-272-24-1

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4

JUNE 1998

TM-9-2320-272-24-1 - Page 242 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

32. HORN INOPERATIVE

Test 1. Test horn circuit breaker voltage.

Step 1.

Place battery switch to OFF position.

Step 2.

Disconnect lead 10 from circuit breaker.

Step 3.

Place battery switch to ON position.

Step 4.

Set multimeter to 50-volt range.

Step 5.

Connect multimeter negative lead to vehicle chassis ground and positive lead to lead 10.

Multimeter should indicate battery voltage.

a.

If battery voltage is not indicated, perform malfunctions 2, 3,4, 6, and 7.

b.

If battery voltage is indicated, go to step 6.

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