Title sums it up. Basically, my Driver side (Coupe for what it's worth) blind spot indicator lamp is almost always on. It seems like it gets "confused." For example. There will be no cars around and it will turn on. It will only then turn off if a car passes me on the driver side. Sometimes it'll then stay off until the next time a car enters and leaves the blind spot (thus staying lit again) and other times will just light back up with no other vehicles in sight.

I did take it to MB once. They removed the bumper and said they reversed some cables as per a service bulletin.. Problem seemed to have been resolved for a few weeks but lately its been really acting up again.

I'm going to bring it back in (which means my car will sit for ANOTHER week) soon, but curious if others have had a similar issues/remedy.

Also, would this justify a lemon after 3 repairs? I don't want it to be, but this was a $70k vehicle and I know people with $25k vehicles that have near flawless blind spot indicators.

 

The sensor module is mounted under the bumper fascia and it's not a big deal to change. As for reversing wire that sounds like a story. The plugs are made to only go one way so the assembly line gets it right. Tell them to show you the service bulletin otherwise it's BS. They can do this in a couple of hours, why does it take a week? You have dealer issues.

 

The city I live in is a pretty hot spot with a lot of snow birds. This time of year the deals get flooded with people getting back for the winter and having their winter cars serviced.

That said I wont take it back to the first dealer, who claims to have "fixed" the light issue. I got word from the second dealer that the reason Dealer1 wins so many awards from MB is because they simply weasel out of doing warranty repair work, hence why they "couldn't find an issue" with my drive shaft after 4 days of testing, but Dealer2 knew what is was just by talking on the phone.

It does sound like a pretty easy fix though. I just need to document it when it happens, because of course when i take the car in it never acts up during the test drive with the technician. I'll have my girlfriend video tape it next time as evidence.

 

FWIW, I have a 2019 coupe and have not had this issue.

 

did you ever solve this? Exactly same issue here and out of ideas

 

I have the exact same issue but on the passenger side of my 2019 C300, which I bought new in 2019. Took it to the dealership at least twice during which they kept it for over 3 weeks, changed bumper and sensors, but made no difference. I have been reminding them at least once every year during service that the issue has not been resolved. I also wrote to MB USA but all they said was to take it to the dealership service. And now 5 years later, with warranty expired, I still have the same issue. I write to MB USA again but all they said was to work with the dealership (the service advisor has since quit) and pay for the diagnostics. They might assist with the repairs. So no offer from MB that they would foot the bill for everything related to addressing this issue. I am thinking of exploring my legal options at this time to see the vehicle can be declared a lemon

 

On my 2019 C300, the Blind Spot Assist warning (warning beep and red warning triangle in side mirror) comes on every time the indicator on the right is turned on, whether there's another vehicle in the blind spot or not. The red warning triangle does not stay on when the indicator is in the off position. The indicator on left side works correctly. If it's a matter of replacing the right hand side sensor module mounted under the bumper fascia, it sounds like an easy fix and a DIY, but if dealerships have difficulty with getting this issue repaired, then it's perhaps not simply a matter of replacement. I'd like to fix this myself if possible, but I don't want to buy parts that don't resolve the issue. If anybody has first hand experience, please let us know. Thank you in advance.