nasa likod ng battery. i'll try to post a pix later. pede mong buksan ang ECU ng C220. You can clean it with cotton buds and alcohol or any quick drying solution. I could recommend an electrician that does home service.
Here it is without the battery. Just to add, the green relay on the left is the FPR (fuel pump relay), the empty space before that is where the Klima relay should be. On the right of the ECU is the OVP (over voltage relay). These are the vital relays to check, of course there are more behind the fuse box.
