I have tried to browse the hundreds of stereo related threads to see if something similar had been posted before but did not see it. If this has been posted and I missed it, sorry for the repost. Maybe it will be helpful for future newbie Mercedes drivers, so I will start with the basics that most seasoned MB owners already know.

Yes, a new stereo would be the best route to get the most out of your MP3 player but for some of us the upgrade hassle isn't worth it. For those of us who get by with the standard stereos in our mid 1990’s and later MB's, one of the biggest irritations is trying to use an MP3 player through the factory supplied MB stereo. In my opinion, the after-market transmitter devices don’t cut it due to poor audio and poor reception. I have read about people developing workarounds to add audio ports through the back of their stereos but I don't want to deal with that aggravation. Therefore, to me, the cassette adapter has the best mix of reasonable audio quality and ease of use/install. The only problem is that you need to shut the cassette door on a factory MB stereo or it will start beeping at you non-stop through the stereo’s speakers. The key to stopping the beeping is to fool the indicator which signals that the door is closed.

With the cassette door open, the indicator can be found in the upper right-hand corner of the frame around the outside of the opening for cassette insertion. See “A” in the image below. Look in the hole and you will see a small pin. All you have to do to stop the beeping is to insert something into that hole which presses the pin inward. You can see the plastic stud on the swinging door (marked “B”) that accomplishes this task when the stereo door is closed.



The tricky thing to find is a round object to insert that is the exact correct diameter. Too wide, and it won't fit. Too narrow, and the spring-loaded pin will pop your plug out due to lack of friction.

My solution was to buy a $.43 dowel rod from Home Depot (the smallest one they sell), cut off a few 1.5 inch lengths, sand the ends flat and smooth, then wrap one end with a few turns of electrical tape. You customize the thickness by the number of turns of electrical tape. Cut off enough tape for 5-6 turns of the dowel and then keep shortening the tape until you get a decently tight fit. (Don’t start too short and then try adding extra pieces of tape because the small pieces of tape will separate too easily.) My particular dowel took about 2.5 turns of tape. Electrical tape is flexible and it has a grippy surface (not to be confused with the sticky side of the tape!) to create friction which keeps the dowel from getting popped back out by the pin.



Make 3 or 4 of these sticks in case you lose one on a trip (I have already had to dig under the seat to find one). What I am showing here are just my first attempts at a prototype. You can make them shorter or longer (make sure they are easy for you to be able to grab). I am thinking I will put a knob on the other end to make it easier to grab.



Many will laugh at this simple solution but it works for me, especially since I only use my MP3 player on trips when I know I will be driving for longer periods of time (vs. the constant in and out during errand trips around town).

Doug