2009 E 350 Turn Signal Problem

2009 E350 Turn Signal Added a Trailer wiring harness about 3 months ago. Last week turn signals went out. Fuse was blown. Replaced. Today signal started flashing quickly so thought I had a blown bulb. Throughout the day on a 500 mile + trip I had right signal that worked, then right signal that didn't work. Any ideas?

May be your bulb is burned out or bulb socket is bad. Also there may be a chance for faulty in wiring going to the bulb. This may be built-in warning to you that the bulb out.