Can someone tell me what the opt button on dash if fo on a 2017 Dynamax XL. From my understanding this year does not have the air dump. The light comes on but I can’t find anything it does. I thought it was covered when we bought it used but I missed it or forgot.
It's an aux switch for you to wire up most likely. That's what it is on my 2016. I used it for my light bar backlight. Beware its fairly low current. Under 10A I believe.
There is a thread here somewhere where someone traced the wires. They end under the drivers side of the rig. I wired mine to rear facing dock lights as I call them.