@vtrn_raptor It's an indicator relay I believe, if you type the part number into the search box on Fowlers webby, it will tell you which bikes use that part. Just scroll down to find the year of your DTR;
https://www.fowlersparts.co.uk/parts/view/29U-81950-93?gclid=CISM1Za6jdUCFW4A0wodj9AJOw