What a trip! So much unfortunately incorrect or irrelevant advice.

This thread is relative to those with the US-market Becker Audio 30 / BE 6003 radio. This is the radio that came in my NON-AUX, NON-NAV, NON-CD, base model 2001 CLK 320. I say US-market, and specify these features which other radios often have, because I have read Audio 30 was less primitive in the European market and is likely not wired the exact same way.

Wiring and electrics, car stereo -- far from my forte. I kept reading how easy and "plug and play" these radios are to install and convinced myself to purchase the radio, at a lesser cost than paying Becker to put a BT unit in the back of my original head unit. After cashback, the Conti was $100, I got mine via Walmart. Note: if you are buying this radio online, make sure not to buy the 24v version(for boating or otherwise). Even the box on mine it said 24v and I thought I did a whoopsie, but inside was the 12v.

Back to the problem: people told me "the plugs are the same on the Continental radio as they are on the Becker radio"; if you buy this and have a 2001 SLK 320 or CLK 320(or otherwise) that has this BE 6003 radio, and you go to install it, that's likely the first misconception you are going to find out. One plug is NOT the same.

A = power(same but wired different)
B = wiring(same)
C = steering wheel controls(different)

While the A and B plugs can be used, the C plug on the Becker has vertically mounted pins, and will not fit. The Continental has horizontal pins for plug C, unlike plug A+B. Fortunately, not using this plug this mainly just robs you of your steering wheel controls.

So, I tried it, excluded the C plug, and voila. No power to the radio with only the A+B plugs.

Commonly suggested when reading about this radio is "switch the A4 and the A7 pins". Now, I've never depin'd a radio before and simply didn't want to get into this stuff out of fear and paranoia, destroying my wiring harness and being left with a stock unit I can't use. But here I was. I went with the Continental because I thought I could do it on my own, for cheap, and have a normal head unit in one of my old cars(for once lol). So, then came the realization. 'If I'm to keep the radio, I'm going to have to depin'. The problem with following this advice? This BE 6003 radio does not have an A-connector 12v switch pin. It has a 12v constant, but that's what comes plugged into A4. Meaning, if you go and switch the A4 for the A7 plug, the radio is not going to turn off when the car turns off, because it has constant power. So, this is exactly what happened. I was stoked to have power, but then I had to unplug the radio so it didn't kill my battery overnight.

I spent a bit of time trying to find wiring diagrams and posts from anyone at all who actually has this radio. No luck, really. I messaged a guy with an SLK who had inquired about having this same problem with this same radio, but he got no responses and has yet to respond to my own inquiry about it.

I have acquired some degree of a victory here and will explain it in this short DIY. Again, YOU MUST HAVE A BE 6003 radio and I bet if you have ANY other radio in a Mercedes this is NOT the case. Literally ANY other stock radio and you don't have this same problem. Idk if there's one single other model with a wiring harness that can be modified in this specific arrangement in order for it to work.

DIY Solution for Becker 6003 with (probably most) Continental radios designed for old European cars/ISO connectors:

1. Buy the Conti radio somewhere. Buy radio removal tools($1), and an automotive depinning kit($5) on ebay, Amazon, etc.

2. Keep the car off with no key in the ignition, or ideally disconnect the battery.
Remove the old radio using the removal tools. The curve of the 'blades' should both face inward on either side of the radio.

3. Unplug the 3 connectors from the back of the unit, remove the disc changer plug, as well as the wire to the antenna connector.

4. After attaching the antenna connector that comes with your new radio to the back of the new radio, reapply the original antenna wire to the new head unit.

5. You will see the B plug is all thin speaker wires, but the A plug is easy to differentiate as the power plug, because it has a fat brown ground wire. Feel free to plug the B plug in before or after working on the A plug.

6. Working on the A plug...
First, use something skinny from your pin removal kit to push the little piece of grey plastic out of the connector. You will have no luck removing the A4 pin if you do not slide out this grey plastic piece. It is very easy to get in and out.
Once the piece is removed, go ahead and use an appropriate sized depin tool on the front side of the connector, in order to squeeze the body of the pin, and then gently pull the pin out of the back of the connector.


7. Relocate the A4 pin to the empty A7 slot, and reapply the grey locking piece back into the A connector.
Connect the A plug to the back of the radio, and the B plug if you have not already. Install the radio and apply the faceplate.

Using the radio: Now, there's but one downside of doing this very simple method and that has already been stated: the unit has constant power. But, if you hold down the radio power button for 3 seconds any time you shut the car off, the radio(and backlight) goes off too. If using BT, powering the unit off this way will automatically disconnect from your phone. There might be a more complete solution out there, but I haven't been able to find it. You can definitely nab a switch 12v line from a different component, but I haven't looked into that and don't think that's something I'll do. For example people say use the cigarette lighter(which I use for other things, and don't want to compromise). Thusfar this method has allowed me to use the radio with only having modified one pin on the original connector.

Best of luck if you in this predicament with your BE 6003 radio and feel this solution is worthy. Feel free to ask any questions.

 

Additionally, there is also something on these radios called "Logic Mode". I have yet to figure out how to get into the option, but it's supposed to be able to automatically turn the radio off when the ignition is off -- even without an ignition signal.

 

I haven't looked into Logic mode since this post and can comment that, as far as I can tell, with the radio wired this way, even if the car is left on, when you exit, as long as your bluetooth is disconnected, the radio will power down on it's own. That said, I've left it on a few times where my phone reconnected to it as I'm pacing inside my house, and the person I was talking to started playing through my car.