supposedly, the blue/blk wire (top right pin) from the oem harness on my 07 w203 is the acc 12v+. however, the same wire didn't activate my aftermarket amp. so I got the power from the front cig lighter. does that sound right?

 

crimp your remote wire from your after market amp to the blue blue remote wire on the back of your headunit... that's what i did...when u hit power on the deck...it turns on the amp..