When I'm driving around town in my Burb, the lights all work great, but for some reason if I use the right turn signal while headlights or running lights are on, it fast blinks like there's a bad bulb.

This only happens when the running lights or headlights are on. When they're off the right signal works as normal.

Any thoughts on how I can chase that down? Thanks!

 

I'd check for corrosion in the turn signal lamp sockets, or bad ground connections.