Retrofitting trailer coupling wiring harness - AN31.19-P-8100-05TA

Fig 1: Retrofitting Trailer Coupling Wiring Harness Diagram

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Fig 2: Identifying Trailer Coupling Wiring Harness, Trailer Connection Unit, Operating Unit And Trailer Hitch Socket

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1. Install impact absorber (17) on trailer hitch crossmember.
   Fig 3: Identifying Impact Absorber

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2. Route trailer hitch wiring harness (20) in cutout of impact absorber (17).
3. Guide wiring harness for trailer hitch (20) through the existing opening below the left taillamp and secure with grommet (18).
   Fig 4: Identifying Trailer Hitch Wiring Harness, Impact Absorber And Grommet

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4. Route the trailer hitch wiring harness (20) along the existing wiring to the trailer connection unit [AAG] control unit (N28/1).
   Fig 5: Identifying Trailer Hitch Wiring Harness And Trailer Connection Unit Control Unit

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5. Connect the black 6-pin coupling and white 4-pin coupling from the trailer hitch wiring harness (20) to the trailer connection unit [AAG] control unit (N28/1).

   The couplings are coded.

   The trailer connection unit (AAG) control unit is mounted in an aluminum bracket (arrow) on vehicles with code (220) Parktronic system (PTS), with code (475) Tire pressure monitor (Beru), with code (527) COMAND APS (with navigation), with code (860) TV tuner, with code (889) Keyless GoN28/1).

   Fig 6: Identifying Trailer Hitch Wiring Harness, Trailer Connection Unit Control Unit And Left Side Tail Lamp

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   Fig 7: Locating Trailer Connection Unit Control Unit Mounted In Aluminum Bracket

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6. Connect the brown wire from the trailer hitch wiring harness (20) to the luggage compartment ground at the left-side taillamp (W6/1).
7. Connect the two black 4-pin couplings and black 8-pin coupling from the trailer connection unit [AAG] control unit wiring harness (22) to the trailer connection unit [AAG] control unit (N28/1).

   The couplings are coded.

8. Connect the brown wire from the trailer hitch wiring harness (22) to the luggage compartment ground at the left-side taillamp (W6/1).
9. Route wiring harness for trailer connection unit [AAG] control unit (22) along the existing lines to the rear SAM control unit with fuse and relay module (N10/2) and secure.
   Fig 8: Identifying Trailer Connection Unit Control Unit, Relay Module, Left Side Tail Lamp And Trailer Hitch Wiring Harness

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10. Insert violet 5-pin coupling (vi) from trailer connection unit [AAG] control unit wiring harness (22) in violet slot (15) of control unit of rear SAM with fuse and relay module (N10/2).

    The coupling is coded.

    Fig 9: Identifying Violet 5-Pin Coupling, Violet Slot, Relay Module And Trailer Connection Unit Control Unit Wiring Harness

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11. Insert the turquoise-colored fuse holder with fuse 17 (N10/2f17) and the black fuse holder with fuse 18 (N10/2f18) into the rear SAM control unit with fuse and relay module (N10/2).

    The fuse positions are color-coded.

    Fig 10: Identifying Turquoise-Colored Fuse Holder And Black Fuse Holder

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12. Remove the nuts (30) and remove the bracket (31).
    Fig 11: Identifying Bracket And Nuts

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13. Route line branch-off with black 4-pin coupling from trailer connection unit [AAG] control unit wiring harness upstream of rear SAM control unit with fuse and relay module (N10/2) in cable duct (33) to trailer connection unit control panel (A63/1).
14. Fasten line branch-off on left longitudinal member with felt strips.
15. Route line branch-off with black 4-pin coupling along existing lines to the trailer connection unit [AAG] operating unit (A63/1) and fix in position.

The coupling is coded.

Fig 12: Identifying Relay Module, Cable Duct And Trailer Connection Unit Control Panel

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