your probably right. the 5 star has a pretty messt wiring setup having a battery and stuff, so it can be a confusing nightmare to figure out. test the bulbs with a meter for continuity, make sure the ground wire on the rear fender has a good clean connection, and test the continuity of that switch. shouldnt be too hard to diagnose once you know where all the wires go. check the switches in the brake cables as well.