prstu

Hi, new to the forum and trials, from more an Enduro / Green laning background. Bought a 2nd hand Pre 2015 Oset 16 36v for my boys Christmas present, seems to run ok, but the part of the harness highlighted in yellow in the image is broken and not connected. It looks like an in-line fuse to me, but also looks to be in a useless loop. Could someone let me know what it is please as I likely don't have time to order a wiring harness mail order before Christmas, but could repair it. Although as stated it runs, so don't know if it's part of something else, charging maybe? I've tried looking at the wiring diagrams online, but it doesn't appear clear, at least to me. thanks