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 120 of 1275

TM 9-2350-311-20-1

3-3 TROUBLESHOOTING CHART — CONTINUED

b. MASTER RELAY CIRCUIT — CONTINUED

(1) MASTER SWITCH INDICATOR LIGHT IS LIT –

CONTINUED

CONTINUED FROM STEP A

1.

2.

3.

4.

5.

Reconnect lead 459 to master relay.

Disconnect bulkhead-to-headlights/biilge

pump wiring harness from driver’s bulkhead.

Place red lead of multimeter on pin H (lead

459) and black lead to ground.

Turn MASTER switch ON, and check for

voltage.

Turn MASTER switch OFF.

Is voltage present?

Repair or replace lead 459 of

bulkhead-to-headlights/bilge pump

wiring harness (para 8-47).

1. Reconnect bulkhead-to-headlights/bilge

pump wiring harness to driver’s bulkhead.

2. Disconnect lead 459 from bulkhead-to-

portable instrument panel wiring harness

connector.

3. Place red lead of multimeter in lead 459

and black lead to ground.

4. Reconnect battery ground leads.

5. Turn MASTER switch ON, and check for

voltage.

6. Turn MASTER switch OFF.

Is voltage present?

Repair or replace lead 459 of

bulkhead-to-driver’s instrument

panel wiring harness (para 8-50).

CONTINUED ON NEXT PAGE

3-20