So I got some new super bright leds to replace with my stocks bulbs but the left light doesn't work…. Even with the stock bulb in, still doesn't work. I think it has to do with wiring… I noticed that when I slightly closed the trunk the light would go on and when I let the trunk go back up it would turn off. Idk whats going on, I know its not the little black module or whatever that clips onto the trunk that the wire plugs into because i switched it over to the right side and it works perfectly fine. SOMEONE please help, this really bugs the SH#T out of me….

 

i have these http://www.ebay.com/itm/2-Error-Free-LED-License-Plate-Light-For-MERCEDES-BENZ-W220-S320-S420-S430-99-05-/321373815239?pt=Motors_Car_Truck_Parts_Accessories&hash=item4ad35f41c7&vxp=mtr

 

I was thinking about getting those too. I thought my housing might be the reason but its not because I unplugged them and switched them around and it still worked. I think it has to do with wiring... Idk what to do now, my leds work perfectly fine.

 

If they work fine, then happy days. Do double check the wiring. Also, check they are the right width bulbs, there are others that are 2mm too short, and they have issues.

 

Would you know how to get to the wires for license plate lamp holder?

 

You have to remove the trunk liner, its easily accessible behind there.

 

Do you have the same problem? Like Alex said, start by unscrewing the three screws that hold the plastic cover on the bottom side where the lock hing is then you'll be able to pop the liner off. Becareful because there's two wires that's conectted to it that you have to unclip. Hope that helps.