TM-9-2350-311-20-2

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

TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS

DECEMBER 1993

TM-9-2350-311-20-2 - Page 173 of 828

TM 9–2350–311–20–2

3–62

3–3

TROUBLESHOOTING — CONTINUED

e.

CAB HYDRAULIC SYSTEM — CONTINUED

PICTORIAL VIEW

ELECTRICAL SCHEMATIC

CAB POWER PACK HYDRAULIC PUMP DRIVE MOTOR CIRCUIT (M109A4/M109A5 HOWITZERS)

1

9

5

8

10

6

2

3

4

7

1

8

7

10

5

3

2

4

1

11

A

645

LEGEND:

1. Contact arm assembly

2. Power relay box assembly

3. Pressure switch

4. Power pack assembly

5. Gunner’s selector switch box assembly

6. Segment board

7. Power valve solenoid

8. Clutch valve solenoid

9. Traverse bypass valve assembly

10. Elevation selector valve assembly

11. Hydraulic pump motor