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 124 of 1275

TM 9-2350-311-20-1

3-3 TROUBLESHOOTING CHART — CONTINUED

b. MASTER RELAY CIRCUIT — CONTINUED

(2) MASTER SWITCH INDICATOR LIGHT FAILS TO

OPERATE; MASTER SWITCH IS ON — CONTINUED

CONTINUED FROM STEP B

1. Reconnect lead 459L to MASTER switch

indicator light.

2. Disconnect lead 459 from MASTER switch.

3. Place red lead of multimeter in MASTER

switch and black lead to ground.

4. Turn MASTER switch ON and check for

voltage.

5. Turn MASTER switch OFF.

Is voltage present?

Replace or repair lead 459 of portable

instrument panel wiring harness (para

1. Reconnect lead 459 to MASTER switch.

2. Disconnect lead 459B from MASTER switch.

3. Place red lead of multimeter in lead 459B

and black lead to ground.

4. Turn MASTER switch ON and check for

voltage.

5. Turn MASTER switch OFF.

Is voltage present?

1

Replace MASTER switch (para

8-17).

CONTINUED ON NEXT PAGE

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