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Replacement

Individual modules within the AMU can be replaced.The replacement may vary slightly for each module.The following is a general replacement procedure.

1. Park the vehicle on a level surface, shut downthe engine, apply the parking brakes, and chockthe tires.

2. Disconnect the batteries.

NOTE: Pressure Switch "A" (Fig. 1)is equippedwith a shut-off valve that will stop air from flow-ing to the modules to the left of the switch. Thisvalve can be used to shut off air to the modules.

3. If replacing Pressure Switch "A", drain the airreservoirs. If replacing any other module, turn theshut-off valve on the pressure switch to the OFFposition.

IMPORTANT: Clean the AMU and the areaaround it of all dirt and road debris before re-moving any modules. Failure do to so can resultin dirt or road debris between the modules andtheir seals, causing air leakage.

4. Loosen the bolts on the L-bracket securing theair management unit (AMU) to the frame rail

mounting bracket. See Fig. 2.This will allow theAMU to separate, allowing for easy removal ofthe module.

IMPORTANT: Be sure to mark all airlines beforemoving them from the modules.

5. Mark and disconnect the air lines (and electricalconnectors, if applicable) from the module to bereplaced.

6. Pull out the locking keys from both sides of themodule tobe removed and slide the AMU apart.See Fig. 3.

7. Remove the module.

8. Install the new seals on the sides of the module.

9. Place the new module in position and slide themodule AMU together.

10. Push in the locking keys.

11. Install all air lines and electrical connectors aspreviously marked.

12. Firmly tighten the bolts on the L-bracket, secur-ing the AMU in the mounting bracket. See Fig. 2.

13. If any other module besides Pressure Switch "A"was replaced, turn the shut-off valve on the pres-sure switch to the ON position.

12/19/2001 f543857

1

2

3

245

6

7

1. Electrical Connector2. Application Supply Air Ports3. Primary Supply Air Port4. Secondary Supply Air Port5. Shut-off Valve6. Secondary Air Internal Delivery Port7. Non-Thru Port

Fig. 1, Pressure Switch Module "A"

09/07/2001 f430272

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3

4

5

1. Crossmember2. AMU3. L-Bracket Bolt4. L-Bracket5. AMU Mounting Bracket

Fig. 2, Air Management Unit (AMU)

Air Management Unit 42.19AMU and AMU Module Replacement

Business Class M2 Workshop Manual, Supplement 1, April 2002 100/1

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14. Connect the batteries.

15. Remove the chocks from the tires.

08/09/2001 f4222611

A

A. Separate the AMU to remove the module.

1. Lock Key

Fig. 3, AMU Module Replacement

Air Management Unit42.19AMU and AMU Module Replacement

Business Class M2 Workshop Manual, Supplement 1, April 2002100/2