85 Brat blowing turn signal fuse when shifted into reverse

[Uberoo]

I'm posting this for a friend: Anyway, I have a friend with an 85 brat with a 4 speed DR that just recently has started blowing the fuse for the turn signals when its shifted in reverse.Its not every time but it only blows when shifted into reverse. I'm thinking the reverse switch is faulty, but is there anything else that would cause the fuse to pop when its shifted in reverse?

[naru]

Probably not the switch.

More like a backup bulb or socket shorted to ground.Could be the wire from the switch to the bulbs too.