If you have an override reverse (yellow) button and it does not kick it into AWD while in reverse (Icon in 4 wheel and SLOW blinking), you may wish to check the harness as it plugs into the switch/box itself. They get extremely dirty and that can cause issues. I suggest that you unplug the wires from the side of the override box (on left handlebar) and blow it out with compressed air (compressor?)... In many cases, they should be quite a dust storm from the plugin and the hole you unplug it from. You may also need to use a needle to pry the contacts up a bit, but be careful not to break the contacts. When reinstalling the plug, be sure to slide it straight in and not up/down/sideways... It needs to go straight it.... Do the same with the next plug in.... I have done this on several Sportsman 500's and it's worked every time... Some dealerships have replaced the box on a recall with no charge... Other dealerships, from what I was told, charged $100's to replace the wiring harness and all they did was what I have stated.... Hope this helps with the frustration and save's you $$$$$$..... Respectfully,