S type vibration at speed and electrical problem in drivers door

[actros]

My s type drives well until it reaches 70+ mph then it develops a rear end vibration - any ideas?

Problem no.2 is a strange one. Drivers door switch bank works fine with everything working except when I turn the lights on then nothing works from this switch bank. All other window switches continue to work as normal albeit with no back lighting again, any ideas.

Thanks guys