Mercedes-Benz 80054, 8801, 8812, 5558, 8731, 8800, 8817, 8802, 8

1. Please pull out the fiber optic cable from the original connector and plug it into the blue MOST audio adapter. Please check the attached picture here.

Connection diagram here.

Fiber optic MOST adapter connection instructions are below. 
1. Yellow: positive of the battery (usually the yellow wire from the aftermarket head unit main harness).
2. Red wire- ACC wire(usually, it is the red wire from the aftermarket head unit main harness).
3. Black wire-GND(usually, it is the black wire from the aftermarket head unit main harness).
4. RCA audio input connects to the Front left and Front Right audio outputs of the aftermarket head unit
5. The fiber optics plug connects to the fiber optics plug on your car.

2 . It does not show the Mercedes logo due to copyright reasons.

The yellow antenna is unused. The new radio does not need it.

3 . You can not change the dash clock through our radio. However, you can adjust it through the steering column switches. Here is a video FYI: Video link here

MB-880054 Connection diagram here. Sent by Order #9569, Zac Nettles
Factory radio pins and numbers here.
Factory radio pinout explanation here.
MB-88054 manual Connection map here.

MB-80054 in NTG 1 manual connections: The canbus decoder is for the steering wheel control buttons, volume, next/previous track, etc. It also detects the reverse gear and switches the radio screen to the reversing mode. ACC detection: if the ignition is turned on or off, it sends 12v+ to the red wire. But you have connected that manually. Connecting the canbus green wires will only enable steering wheel control buttons. 

Mercedes interior CAN lines are typically solid brown (CAN Low) and brown with a red or black tracer (CAN High). At 5:03 in the video below, it shows the location of the canbus wires in an SL550 R230 2008. https://www.youtube.com/watch?v=-hFWfDA1IDA.

About the sound: Please check if the MOST adapter is turned on. Also check if there is any faulty module in the car; please use the bypass loop adapters included if needed.

CD Changer - Behind the driver’s seat, remove all panels until you get to the amplifier. Here’s a youtube video that helps with that.
Cell Phone - Behind the center console, there is a panel that is removed in the process of getting to the amplifier (between the two rear storage boxes). You will see the fiber wire running and a module in the center that needs to be disconnected.
Voice Control - This unit is next to the amplifier (under the storage behind the driver's seat). I believe the connection is underneath, so you will have to look closely for it.

When unplugging these devices, you need to remove the fibre optic connectors and install a connector loop between the two ends. The part number to accomplish this is 000-545-33-84. To remove the original connectors, it’s simply a case of pulling a grey “key” out of the lower side, and the wires will come out. One thing I have learned that is huge is to wrap these new loop connectors in electrical tape: they will ground out otherwise, which causes audio to cut out until the amplifier restarts.

8817 D2B: You also need to use the MB part # 000-545-33-84, which connects the two ends of the D2B plug together (this is accomplished by removing the fiber ends from the plug) and wrap these new loop connectors in electrical tape: they will ground out otherwise, which causes audio to cut out until the amplifier restarts. This is the OEM part, and we do not sell it. You can buy 3 pieces through this link: 3 pcs of this item to bypass the CD changer, Voice command module, and phone module: link here

HL-8817: Bypass the CD changer and voice command module video: https://youtu.be/1DQoxBKvoq0

HL-8801 PDF connection map R171 here. The yellow fiber-optic MOST should be connected to the yellow number 1.

HL-8797: The FM antenna plug and CAN BUS data connector are on the same module. It is located on the left (driver) side inside the trunk. Here is a photo: link

Our radio is compatible with the car. However, the installation is not plug-and-play. However, you must cut and splice the wire per the attached wiring map.
1. You will need to cut and splice five wires. Please take a look at the attached picture.
2. You also need 3 PCs of the loop to bypass the CD changer, phone module, and voice command module. We will include them in the package. link here
3. You also need to buy an external FM/AM antenna; for example, this one: 

1. You can add our extension wire. This wire will be connected to a connector that will be removed from the factory amplifier in the trunk. Using this extension wire will connect only 4 speakers in your car. The factory amplifier will be bypassed, and the sound quality will degrade. Link here to the extension wire. 

2. You can use our MOST fiber optic adapter. All the speakers and factory amplifiers will work the same as before. The sound quality will not degrade. However, installing the MOST adapter is not plug-and-play. You have to connect 3 power wires and 2 CAN wires manually. 

Here is the connection diagram of the MOST fiber optic adapter link