20 Most Recent 2012 Mercedes-Benz M-Class ML350 4MATIC 4dr SUV 3.5L V6 AWD 7-speed Automatic Questions & Answers

Try the manual https://www.mbusa.com/mercedes/service_and_parts/owners_manuals

Make Sure the Battery is Fully Charged,This can be done by Headlights or Horn.OK.

Radios naturally come with am, so it will always work so long as there's power to the radio. Fm, however, is a built in receiver and if they break or start to break, then you will lose power to your fm which it sounds like is starting to happen to you.

In the underbonnet relay box but if its not been recharged then it won't run anyway.

have a look at this

it seems like be faulty crank angle sensor