Key fob and Electrical fail after starting

[Rdublin]

I badly need help please , I have a 2003 c180 , when I put the key fob in sometimes it doesn't register making that clicking sound but if I give the fob key a tap sometimes it works , so more then likely I'd need a new key ??? But when it does work the electrics would work while ignition is switched on but when I start the car they just shut off no indicators, wipers , radio and clocks there all gone gauges are gone too but the engine would run and the car would drive perfect could this be the key fob aswell I'm badly stuck and need help please . Thanks

 

[Benza750]

You need to get it on star diagnostics so that the actual values and live data from the ignition can be read when key is in ignition.
You may have 2 faults, 1 with key & 1 with ignition switch.
Even a faulty steering lock can cause you problems.
It is a dealer or good independent job with correct diagnostics for mercedes.
You carnt use second hand parts for any if the above, all dealer only

 

[Rdublin]

Cheers thank you for the help , I'll have to arrange to get to a dealer hopefully not too exspensive I was hoping it was just the key fob

 

[Benza750]

A new key costs £227