Yes, that's the box that contains the RCM. Watch the video. I see you've installed a rapid disconnect on your battery so pulling and checking the internal relays of the RCM shouldn't be overly spooky. If you are spooked, just buy a spare RCM and try that or keep it in the car as many others do because the stock RCM has a tendency to fail and create the dreaded N0-Start problem due to failed solder joints that can come at any time. Even if you totally screw the internals of your RCM up you can toss in a new replacement and forget about it. Prices of these things tend to bounce all over the place and I see today it is $160 on Amazon that is quite high. I paid about $120 for mine and others have scored some as low as $90. You can search and maybe find a new SMP brand for less than $160 but even at $160 it's still not pricey when you consider what a tow will cost ya, the hassle of being stranded and then probably ending up at some Chrysler dealer that is gonna rape ya with technicians who know nothing about these Mercedes based cars.