I recently started having problems with my W204 200 cdi class. I placed the key in the ignition but nothing happened. I turned the key but no lights came on. I took the key out and back in again but still nothing. However, eventually, after several attempts, the dash lights came on and I got started.
I took the car to my local garage and they tested and found the car battery needed changing. Now battery in and car's seemed fine, however, the same problem had started again.

Key into ignition but no connection sound. turning the key and no lights come on. After many attempts taking the key out and back in again, I eventually got it to start.

Any help please??