I'm new here and recently worked through some strange taillight behavior interfacing our 2014 Navion IQ (i.e., Winnebago View) to our 2018 Buick Envision recently outfitted to be our Toad. For us, it turned out that the Sprinter trailer electronics are set up for incandescent lamp loads and not the lighter, LED loads on our Envision. The MB technician that I talked to indicated that anomalous behavior shows up differently for different people. For me, the right turn signal wouldn't work normally. Left and Stop worked fine. But when signaling to turn right, both the left and right tail lamps would just flash very briefly on a 1-2 second interval. The solution for us was to add a resistive load between the connector and our cable. This is the part we used: https://www.amazon.com/gp/product/B00C4AYR3U
. Now, initially, when I plugged it in, things didn't change. For some reason, it took a few minutes and then things behaved the way they were supposed to. Again, I'm not sure this will solve your situation, but Amazon has a good return policy if it doesn't. Good luck.