1990 Mercedes 300SEL Car Stereo Wiring Diagram

Whether your an expert Mercedes 300SEL mobile electronics installer, Mercedes 300SEL fanatic, or a novice Mercedes 300SEL enthusiast with a 1990 Mercedes 300SEL, a car stereo wiring diagram can save yourself a lot of time. Automotive wiring in a 1990 Mercedes 300SEL vehicles are becoming increasing more difficult to identify due to the installation of more advanced factory oem electronics.

One of the most time consuming tasks with installing an after market car stereo, car radio, satellite radio, xm radio, car speakers, tweeters, car subwoofer, crossovers, audio equalizer, car amplifier, mobile amp, car amplifier, mp3 player, ipod or any car audio electronics is identifying the correct color car audio wires for your 1990 Mercedes 300SEL.

The Modified Life staff has taken all its Mercedes 300SEL car radio wiring diagrams, Mercedes 300SEL car audio wiring diagrams, Mercedes 300SEL car stereo wiring diagrams, Mercedes 300SEL car radio wiring schematics, Mercedes 300SEL car wiring diagrams and cataloged them online for use by our visitors for free. Our automotive wiring diagrams allow you to enjoy your new mobile electronics rather than spend countless hours trying to figure out which wires goes to which 1990 Mercedes 300SEL part or component.

Feel free to use any Mercedes 300SEL car stereo wiring diagram that is listed on Modified Life but keep in mind that all information here is provided “as is” without any warranty of any kind and most of the car audio wiring diagrams listed on our enthusiast website are submitted by the Modified Life community. Use of the Mercedes 300SEL wiring information is at your own risk. Always verify all wires, wire colors and diagrams before applying any information found here to your 1990 Mercedes 300SEL.


If you have any questions pertaining to the audio system in the 1990 Mercedes 300SEL, please feel free to post it at the bottom of this page and either we’ll do our best to find you the information you need or hopefully someone in the Modified Life community will have the information you’re looking for.

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1990 Mercedes 300SEL Car Stereo Wiring Diagram

Car Radio Battery Constant 12v+ Wire: Red/White
Car Radio Accessory Switched 12v+ Wire: Black/Yellow
Car Radio Ground Wire: Brown
Car Radio Illumination Wire: Purple/Gray
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: White
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: 4″ Speakers Dash
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Yellow
Left Front Speaker Negative Wire (-): Black
Right Front Speaker Positive Wire (+): White
Right Front Speaker Negative Wire (-): Black
Car Audio Rear Speakers Size: 5 1/4″ Speakers
Car Audio Rear Speakers Location: Rear Deck
Left Rear Speaker Positive Wire (+): Red
Left Rear Speaker Negative Wire (-): Black
Right Rear Speaker Positive Wire (+): Green
Right Rear Speaker Negative Wire (-): Black


  • Reply Jack Hemer September 24, 2010 at 6:55 pm

    I inadvertantly left an interior light on and it drained my battery. After charging the battery, it says W A I T and I can’t enter the radio code. Any ideas what to do next to get the radio working. It worked fine before the dead battery. Thanks in advance for any comments.

  • Reply ModifiedLife September 29, 2010 at 1:58 am

    Jack, its sounds like your 1990 Mercedes 300SEL radio may be in safe mode or anti-theft mode. Your radio goes into safe mode or anti-theft mode when it loses power. You will need a unlock code to get your radio working again. Radio security codes are usually written in your car manual or given to you when you purchase the vehicle. If you do not have the radio security code, you would have to obtain it from the local Mercedes dealer. Hope this helps. Good luck with unlocking your 1990 Mercedes 300SEL radio.

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