REF/////C63

Hi All -

Turning to the forums for help on the most recent issue with my car. Started as an annoyance but it's turning into a safety issue. About two weeks ago, the nav screen didn't go down when I shut the car off. The next day the screen shut off while I was driving and turned back on a few seconds later. The following week, I noticed the gauges and the screen were flickering (only for a few seconds) as I was driving down the highway. This morning, the radio shut off and the screen shut off while I was driving down the road, and everything came right back on (Mercedes logo showed up, like when you start the car, which hadn't happened previously). And driving down the highway tonight, everything shut off for a split second (headlights, gauges, screen - seemed like everything lost power), though it didn't seem like the engine shut down. When the power came back, a bunch of warnings came up (ABS, service engine) and the traction control light was flashing. I have no idea what's going on. I don't see any issues with the battery connections, but it's definitely worth noting I had the battery and spark plugs replaced at the dealer about a month ago. Given I only drive the car on the weekends, it could just be taking a while to notice an issue they caused (any chance they fried the electronics?). The weird thing is I can drive for 6 hours and have no issue, but then I'll have an issue like the ones I described above. I know it's a long shot, but figured I'd see if anyone has heard of something similar happening. I wanted this one to last another year before upgrading to the W205 C63s, but I can't have this thing dying on me on the highway. Any thoughts?

Thanks and hope everyone has a great holiday.

realjones88

If you have a voltmeter measure across the terminals to see the voltage (and corresponding charge %) the battery is at. The simplest solution would be to put the car on a trickle charger between drives to keep the battery at 100%. Not saying it's your issue, but for less $50 it's worth a shot. I assume the car started up fine so it might have nothing to do with the battery, could be the alternator or similar issue.

zcct04

If the car is fine 99% of the time, it's quite unlikely to be a battery or an alternator problem, and checking with a voltmeter will likely always show things to be fine. It sounds more likely to be a loose connection somewhere. I'd start with the battery cables and make sure they're tight, since those were recently disconnected.

mthis

something like this? my issues was one of the SAMs. front i think.

Merc63

Take it back to the dealer. The wiring in these cars is crazy, tons of it allowed the place.

roadtalontsi

check the battery terminals make sure they actually got tightened. Then take it to the dealer. This is not something you'll be fixing on your own.

REF/////C63

Appreciate everyone's thoughts. The battery terminals were fine. Looked around and couldn't find any other issues. Took it to the dealer and they found a loose ground in the cabin (by the left footwell, controls gauges, nav screen, etc.). Very odd, but luckily an easy fix. Everything is all set now - car is now almost the same as new. Last one I can't figure out is the high-pitched squeal at higher speeds. Video attached (apologies for the angle) - anyone else having this issue? I think it's the sunroof...

Thanks and hope everyone has a great New Year!