Limited brake assist sensor

[Grandteton]

Just drove my new Navion 24D home and the cruise control does not work. Got message “limited brake assist sensor”. I cannot find the sensors to try and clean them. The Sprinter operator’s manual is not helpful. I will take it to the Mercedes dealer but just wondering if there is a simple fix I can do. Thanks

[Winterbagoal]

Why not call the dealer and ask them where they are? I would think if it's to do with "brake assist", they're on the nose somewhere, perhaps the bumper?

[Grandteton]

I called them and they knew about the problem as it has occurred before and I am taking it to the dealer to fix. Thanks again