Right, where do i start. I've recently got my hands on a L322 2004 with a 2012 facelift on it, which i think looks amazing. well that is the good part the looks.. Now the fun part, I knew it had its issues when I bought it, however I need some advice/pointers where to start. So the Main issues i have are, electric windows.. The driver door can control the driver side front and rear window but not the other side, however the passenger front works but the passenger side rear doesn't.. The central locking works, well just not on the front passenger side.. also the electric mirror for the driver side can be adjusted but not the passenger side. I think that's about it for the electrics Now where do i start? I know this is a post with many issues but any help would be appreciated.

Multimeter and power probe and learn how to use them to diagnose the problem. It's most likely the switch but it could be the non working item(s). Hopefully not the wiring between!

It just logic really! There is power to the drivers door, good. Power up the connection at the switch with power probe, to make the non working item work. If OK, replace switch. If not OK, test for power at the item end. If no power, investigate wiring. If power present, check earth. If OK replace item.

But before any of that, check the fuses!

Happy hunting! Very satisfying when you fix it!

Chris - self taught, no expert!!