Turn on my right turn signal and brake lights flash instead

[Scott Haggard]

I've got 2003 gmc Sierra 2500hd. When I turn my right turn signal on bulb lights up but doesn't flash. It's also causes both brake lights to come on and both of them will start flashing.  It's just the right side that does it but it's an intermitten problem. I'm thinking it's in my multifunction switch but not 100% sure. Has anyone else had this issue before? Any help is greatly appreciated