TM-9-2350-311-20-1

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR HULL, POWERPLANT, DRIVE CONTROLS, TRACKS, SUSPENSION, AND ASSOCIATED COMPONENTS

AUGUST 1994

TM-9-2350-311-20-1 - Page 278 of 1275

TM 9-2350-311-20-1

3-3

TROUBLESHOOTING CHART — CONTINUED

n. ALTERNATOR CIRCUIT (M109A4/M109A5) —

ALTERNATOR FAILS TO CHARGE

BATTERIES; GAGE

CONTINUED

INDICATION: NOT CHARGING, UNSTEADY OR

INACCURATE READING — CONTINUED

CONTINUED FROM STEP K

1. Reconnect rectifier to voltage regulator

wiring harness to voltage regulator.

2. Disconnect battery ground leads.

3. Disconnect engine disconnect bracket-to-

bulkhead wiring harness from voltage

regulator.

4. Place jumper wires from socket A (lead 2)

to socket B (lead 400-459B) and from pin C

(lead 3) to battery negative terminal and

pin F (lead 27B) to the positive terminal of the

same battery to apply 12 Vdc to alternator

field.

5. Reconnect battery ground leads.

6. Turn MASTER switch ON and run vehicle

engine at 1000 rpm (oil pressure at 12 psi [83

kPa]).

7. Place red lead of multimeter in socket F

(lead 276) and black lead to ground.

8. Check for voltage.

Is voltage above 27.5 Vdc?

motor circuit (para 3-31).

Troubleshoot

air cleaner blower

CONTINUED ON NEXT PAGE

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