How to Install Sirius on a Mercedes

Mounting and Antenna Installation
1. Install the Sirius radio device mount in your Mercedes. Available mounting options include clipping it to an air vent, attaching to the windshield by a section cup or mounting to the dash directly by screws.
2. Using your damp rag, clean off an area on the trunk or roof of your Mercedes where you would like to mount the satellite radio's antenna. The antenna is a small round or square-shaped piece of plastic that needs direct exposure to the sky for best performance. Wherever you place it, there should be a minimum of 3 inches of metal surrounding the antenna.
3. Remove the adhesive backing on the antenna and firmly press down to secure it to your Mercedes. Ensure that the rubber tail attached to the antenna ends at either the top or bottom of your rear windshield, depending on what location you chose to mount the device.
4. Take the long, skinny antenna wire coming out of the antenna's thicker, rubber tail and run it along your rear windshield. Use the putty knife to push the skinny wire between your rear windshield and the factory rubber window seal.
5. Continue to run the cable down into the edge of your trunk after you have tucked it between the glass and rubber molding.
6. Tuck the antenna wire below the rubber molding in your trunk that is designed to keep water out. Make sure the antenna wire does not interfere with any of the trunk's mechanical moving parts.
7. Run the antenna wire from the trunk through the rear seats. This can be done by folding down one of the rear seats and running the antenna wire along the side of the seat, then folding the seat back up to secure it. Alternatively, you can also utilize an existing plastic wiring harness that holds a group of cables connected to electronics in the trunk.
8. Continue to run the antenna wire through your car's interior. To keep the wiring discrete and out of sight, consider tucking the wire below the floor's upholstery and up around the passenger-side footwell to connect it to the device mounted in your car. Use zip ties to secure any slack in the wire; tuck it underneath the carpeting.
Power and Audio Wiring
9. Plug the power adapter included with your Sirius device into the car's cigarette lighter. Plug the other end into the side of your Sirius device and turn on your car to ensure that the radio device is receiving power and has a satellite signal, marked by indicator bars in one of the upper corners (depending on what specific device you own).
10. Locate the 'Aux In' outlet in your Mercedes. These can be found in the glove box, on the dash or directly on the stereo's face itself.
11. Plug the audio cable into your Sirius device and run the other end of it to the 'Aux In' input in your car.
12. Tune your radio's frequency from FM or AM to the auxiliary station, indicated by 'Aux.'
Activation
13. Turn on your car so the radio device is powered up and tune to Channel 0. Write down the 'SID/ESN' number that appears on the screen.
14. Call Sirius at 1-888-539-7474 and follow the automatic prompts until you hear the 'Activation' option.
15. Enter your Sirius subscriber number when prompted, then enter your device's 'SID/ESN' value when prompted again.
16. Complete the phone-based activation process and hang up. Turn your car and Sirius device off completely and restart them a few minutes later to ensure that the activation was successful and you can receive audio from Sirius satellite stations.