How to bypass the Air conditioner pully?

On that engine you can do that by removing the A/C compressor and adding the idler pulley circled in green. However you will likely need to order those parts through Mercedes because they do not list them as service parts (not uncommon with MB, they like to withhold info a lot) The thing then becomes if you want to spend the money on that or just replace the AC compressor, you can get a replacement compressor through Rock auto for around $2-300.00 and only need to have the system drawn down and recharged. It's not that hard to replace the unit and it's the same steps if you were doing the conversion, have a shop recover the charge, remove the lower splash shield, remove the belt, unbolt the power steering pump and set it aside, disconnect the A/C lines and unbolt the compressor. Reverse the process to install the new one, have the shop recharge it and have working A/C again.