DIY - CLEAN 12V or 5V (USB) Power to Center Console

[slammer111]

I'm sure 99.99% of you have this capped plug inside your centre console. When you pull it out, there's a 10 pin connector that looks slightly bigger than an Ethernet jack. If you coughed up $$$$ for that obsolete V60 option, then this is where the phone cradle cord goes into the car. For everyone else, this jack does absolutely nothing. This was the case for me for the last 6 years. Having a background in tinkering (okay, Engineering), I decided to turn this plug into a generic USB port to charge my mp3 player. A USB charger is basically a +5VDC source. This port can also be wired to output +12VDC (ie cigarette lighter); 90% of the process is the the same. The beauty of this setup is that it is VERY CLEAN. Not sure if this mod applies to 2005+ W203s, but this can be done for all pre-facelift cars ***DISCLAIMER*** I do not guarantee this setup will work or be the same for ALL W203s. We all know how many different versions of W203s MB has produced. For example, the jack in my centre console is upside down compared to the pic below. I HIGHLY recommend you verify the Pin-outs against the data in the Appendix (scroll down) before starting! By reading these instructions, you agree not to hold me liable for any damage to your car and/or personal injury as a direct or indirect result of attempting this mod. One more thing: this will NOT work if you have the PSE or whatever junk for the V60 installed. Okay, you can still do it, but you're on your own as the pins available will most likely be different. Most pictures in this thread are generic, so I've just taken random pics from various online sources. I will try to give credit where possible. Before: (thanks to Moze, I stole your pic)

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[slammer111]

Things you will need:

Multimeter (for testing)
Wires - either buy some, or snip some off an old PC power supply
Soldering equipment (pen, solder, solder wick), epoxy
Slot screwdriver or RJ50 crimper
Exacto knife, wire cutters etc.

DB25 port protector or dongle (same plug as the oldschool printers) - must have at least 1 MALE end
USB extension cord - I used a female USB type A, but you can choose a Mini or Micro USB if you want
RJ50 connector(s) - picked up a pack of 10
5V power supply - I used a Recom R-78B5.0-1.0 (provides 1.0A, many other choices available), ordered online.

Total cost: about $40CAD
Total time: about 3-5h, possibly shorter if you know what you're doing

[slammer111]

The funny jack in the centre console is called a 10-pin, 10-conductor (10P10C) or RJ-50 connector. MB likes to use proprietary connectors to screw us, as usual. Think of it as a 10-pin version of the common Ethernet (RJ45) cable. The wiring for this cable goes into a connector on the right side of the transmission hump underneath the carpet right where the seam is. This wiring then continues to the back of your car on the right side of the trunk (open the liner hatch to see) into a DB25 connector. ALL 10 wires go into this connector.

We are going to use this knowledge to send power through this connector back into the centre console.

This cord will have power ALL the time (ie it's not switched), so the beauty is that you can charge your device even when the car is OFF.

If you have an Argos BT puck installed into that DB25 plug like I do, the mod can STILL be done.

I will list what every pin does (ie the technical nitty gritty details) at the bottom of this thread in the Appendix.

[slammer111]

First we need to get power to this DB25 connector.

If you have VCS and/or V60/Argos installed, you can skip this step.

Open up the rear SAM (behind left panel of trunk, it's located inside the hatch, directly below the 1st Aid kit for the coupe) and stick a fuse into F16 (red arrow). If you currently have nothing here, I'd recommend a 1A or 2A fuse. Otherwise, you probably have a 7.5A fuse in there already, in which case you can leave it alone.

Photo courtesy of Otmal.

[slammer111]

Take your DB25 connector and open it up. Get out your soldering equipment, wires, and power supply.

I used a Recom R-78B5.0-1.0 because it is by far the smallest 5V switching regulator I could find. "Switching" means it is HIGH efficiency, and doesn't just dump out tons of heat. For this reason, I DO NOT recommend an el cheapo 78xx series unless you feel like cooking something inside your car. This Recom component does come in 0.5A and 1.5A flavours as well. I ordered from Future Electronics, but there are many suppliers (such as Allied) that will carry it.

These instructions will pertain to the Recom chip, but any component you pick will always have the same 3 pins: +Vin (12VDC in this case), GND, and Vout (+5VDC).

Find a way to secure the regulator in such a way that you can still close the dongle case. I just epoxied it to the wires.

Solder chip Pin 1 (Vin) to Pin 4 of the DB25 connector. You can strip a small bit of the wire and solder there instead if you want.
Solder chip Pin 2 (GND) to Pins 3 and 11 (ie use 2 pieces of wire) of the DB25 connector.
Solder chip Pin 3 (Vout) to Pin 12 of the DB25 connector.

You can add a Schottky diode in series leading out of chip Pin 3 if you want as "added protection", but I personally didn't as the specifications stated you do NOT need to if Vin is constantly on, which is true in this case (remember, the power to the DB25 is CONSTANT ON). This might only be a problem if at some point you disconnect the car battery with a USB device plugged in, so make a mental note not to do that.

Test your soldering job with a multimeter. Install and secure the dongle to the DB25 connector. If you have Argos, simply place the dongle between the Argos and car connector.

[slammer111]

It's all downhill from here.

Take your USB cord and snip off an appropriate length. This will go inside your centre console, so it helps to measure the length you need while inside your car.

**EDIT**

I just noticed the RJ50 plug in my car is upside down compared to the one at the pic at the top of the thread for some reason. Be sure to do your research on this part! A multimeter and a DB25 extension cord (connected to the port at the back of car) will do wonders here.

If your jack is upside down, the picture will apply to you. See Pic 1. If for any reason your jack looks different, please VERIFY the pin-outs against the Appendix (scroll down).

The PLUG pic shows the pin layout just as you stare into the hole. The JACK layout is as if you are looking straight at the end of the jack. We are going to concern ourselves with Connectors 6 and 7.

Strip the protective sheath off the USB wire and expose about 10-12mm of the smaller internal wires. No need to strip the internal wires.

Determine which wire is + and which one is -. Red should be + and black is -, but doublecheck as this may not be standardized.

Stick the + wire into Connector 6 of the RJ50 jack.
Stick the - wire into Connector 7.

I would recommend you stick the remaining 2 (or however many) wires into the other empty slots into this jack (doesn't matter which one) for strength.

Crimp the RJ50 connector. If you don't have the tool (which I'm sure 99.99% of you don't), this can be done very carefully with a slot screwdriver. Crimp the other end first to secure the cable inside the jack, then take your time crimping each internal wire. Again, test with a multimeter when finished.

Go to your car, and stick the RJ50 jack into the plug. Plug in a USB device such as an mp3 player and test for connectivity. Enjoy your new power source.

Pic 2 is the finished result.

[slammer111]

Some of the information below is courtesy of Randy of EISKits (distributors of the famed/awesome Argos BT puck). Thank Randy for all your help, without you this would not have been possible!


FACTORY MB PSE DB25 Pin-outs (courtesy of Randy) "Connectors" refers to the connector inside the RJ50 jack in the centre console (remember, 10 of these wires go to the centre console)

Argos BT uses Pins 3, 4, 13, 14, 15. All other wires do absolutely nothing if you have Argos installed.

If you have nothing (no Argos, no V60) attached to the DB25 connector, the only Pins you need to worry about are 3 and 4; everything else does nothing.

(All Classes Except "M" Class)
Pin 1 RX GND - Connector 3
Pin 2 Not Used - Connector 1
Pin 3 Battery Negative - Used by Argos
Pin 4 Battery Positive - Used by Argos - constant +12V
Pin 5 Not Used
Pin 6 TX Audio - Connector 2
Pin 7 Battery Feedback
Pin 8 External Power - Connector 8
Pin 9 Antenna Switch
Pin 10 Not Used
Pin 11 Data Out - Connector 7
Pin 12 Not Used - Connector 6
Pin 13 D2B Wakeup - Used by Argos
Pin 14 MIC GND - Used by Argos
Pin 15 MIC Audio - Used by Argos
Pin 16 Battery Positive - Passthrough from Pin 4 thru Argos
Pin 17 Battery Negative - Passthrough from Pin 3 thru Argos
Pin 18 Data In - Connector 5
Pin 19 Not Used
Pin 20 Not Used
Pin 21 Manual Test - Connector 10
Pin 22 Not Used
Pin 23 Ground - Connector 9 - electrically linked to Argos P3,P4
Pin 24 Audio Ground - Connector 4 - electrically linked to Argos P3,P4
Pin 25 Not Used

***

RJ50 Connector-outs

Connector 1 - goes to Pin 2
Connector 2 - goes to Pin 6
Connector 3 - goes to Pin 1
Connector 4 - goes to Pin 24
Connector 5 - goes to Pin 5
Connector 6 - goes to Pin 12
Connector 7 - goes to Pin 11
Connector 8 - goes to Pin 8
Connector 9 - goes to Pin 23
Connector 10 - goes to Pin 21

[gottarex]

you should make a few of these and sell them

[amdeutsch]

Whats withe frenchie spelling in the title;'re' instead of 'er'. Corrected.