My light has always came on but would throw me off due to the R never came on. It seemed w/o the R the reserve light came on late and made me a little nervous. Since getting the R back the reserve light comes spot on and counts backwards. The crappy thing is that when ever the maxi fuse is pulled or power is lost to the bike one has to reintialize the reserve function by installing the stock ecm. I would hope with all the brain power at TM that they could get that figured out where one didn't have to do that procedure with the stock ecm.