Just wanted to add my two cents here because on my 2017 Uforce 800 the high gear indicator light wouldn't come on until the motor warmed up, and even then it wouldn't always work. I finally decided to chase down the problem and thought I would share in case it helps somebody else. The gear position sensor connector (gray colored in my case) is right under the driver's seat, disconnect it. Just like Mr. Kawierider said, take a grounded wire and, one at a time with the key on, touch the pins of the wire going to the dash. You should see a gear position light come on for each one of those. If you do, then the problem is downstream and is most likely the sensor which is located down below, between the crankcase and the CVT housing. Of course you have to remove a lot of plastic to get to it - but what doesn't? The sensor has some copper pads on it that make contact with a pin that is on the end of the gear shift. I tried cleaning those pads and monkeying with that pin, but the only thing that fixed it was replacing it. That sensor is a sealed puck and I think there must be a soldered connection in there that goes bad? I don't know that for sure. Pay attention to the part number when you are ordering, there are different varieties and the part numbers are VERY similar so it's easy to confuse when you're doing a search.