Just traded my 2016 GLA250 for a 2016 GLC300. Just discovered the rear 12v plug for the backseat does not work. Fuse chart showed it to be #447 under the cargo area floor. I’ve checked it and it appears to be ok. Am I overlooking something or am I checking the wrong fuse? Dealership can’t look at it until next week. Can’t imagine why this plug wouldn’t be working..... thanks!