Have Mercedes Questions? Ask a Mechanic for Answers ASAP
Hi, it sounds like the battery died. If the battery voltage is low and if all of this happened while driving the mechanic needs to be looking at the battery and the battery cable connections and the alternator and wiring. Either the battery or the alternator has failed or there is a fault with the cable connections to the battery or the alternator.
As far as the antenna problem is concerned you will most likely need to replace the antenna assembly. I suspect that the mechanic thought that the antenna was draining the battery.
Let me know if you have any questions.