I bought C class 2.2 Petrol Esprit from Germany. I was given two keys remotes. I changed the switch of one because it was not working. Now the Red LED lights up but it does not switch the imobilizer off. I know it needs synchronizing. I was adviced some ways to do it such as pressing the button twice then put the key in and turn to position 2 for 30 seconds. For some reason this does not work. Maybe i am no aiming the remote at the right sensor. My remote key are single buttons and it only switches off the imobilizer it does not lock or unlock the car.
The car I got in Germany so all the books that i have are in German and i understand nothing, huh difficult to learn German trust me!!!. The car looks abit different from what you normally buy in other countries. I come from Malta and the C class in Malta had different finishings. I put some pictures for you so you can see it. The remote seems to be MB as in the book from what i can see it is very similar to the pcitures. But i do not know if this kind of remote can be sychronized or no. My other remote is on its way to stop as the switch is holding together with tape, I guess soon I end up taking the tram to go to work. Please if you can help
I still did not spend enough time with this issue but you might want to check if you can find the OEM alarm control unit from the car. This parts diagram should help you figure out where the OEM parts are located.
I guess if you are afraid of the immobilizer failing you could leave it off, just lock the doors?