Note: Before doing the following, refer to the warnings in paragraph 27.
1. Turn the ignition key to position "ABOUT", then disconnect the negative battery terminal. Pull back the front mat in the passenger's footwell, then unscrew the fixing screws and remove the foot pad from the floor. Locate the security test wire connector that is colored red and disconnect it. This will override the security system.
Driver side airbag
Removing
2. Loosen and remove the two screws securing the cushion on the back of the steering wheel.
Turn the wheel if necessary to gain access to the screws.
3. Return the steering wheel to the straight ahead direction, then carefully lift the airbag assembly up off the steering wheel and disconnect the connector at the rear of the assembly. Please note that the pillow must not be knocked, it must not be dropped and it must be stored correctly with the soft surface up.
Installation
4. Make sure the connector is securely connected and lay the pillow assembly in the middle of the steering wheel, making sure that the wire is not pinched. Install the fixing screws and tighten them to the required torque, starting with the left screw.
5. Connect the red test lead connector, place the foot pad, and fold back the mat. Make sure that no one is inside the car when connecting the battery. Turn the ignition key and check the operation of the security system control pump by turning the steering wheel from side to side as far as it will go.
Air bag control unit
6. Removal and installation of the control unit should be entrusted only to a Mercedes-Benz dealer. When installed, the unit must be tested on a special Mercedes-Benz test bench to make sure that the security system is working correctly. For reference, the control unit is located below the front of the central console.
Airbag contact plate
Removing
7. Remove the steering wheel as described in Chapter 10.
8. Remove the headlight dimmer switch as previously described.
9. Remove the lower part of the instrument panel from the driver's side, as described in Chapter 11.
10. Trace the wire back from the contact plate, releasing it from all appropriate holders and ties. Disconnect the wire from the main harness.
11. Loosen the contact plate screws enough to release the assembly from the top of the steering column and remove it. This will secure the knot and prevent it from turning when it is removed.
Note: Do not unscrew the fastening screws completely and do not disassemble the contact plate.
Installation
12. Before installing, make sure the contact plate is correctly positioned in the middle. This is not difficult to do if the fastening screws have not been removed. If in doubt about the position of the assembly, fully screw in the contact plate fixing screws and turn the assembly insert clockwise until resistance is felt. Starting from this position, rotate the insert back two or two and a half turns to align the fixing screws with the holes, then lightly tighten the screws to lock the assembly in this position.
13 Install the contact plate (ring) into place, making sure the wires are routed correctly and align the recess in the center of the contact plate with the corresponding boss on the steering column. Make sure the slip ring is properly aligned with the column and securely tighten the mounting screws.
14. Connect sockets and establish the remained details in an order, the return to removal.