driver brake light and center tail light and driver blinker light out

All fuses and bulbs checked out.  When I turn on the left blinker it blinks fine for about 3 times and then a fast blink.  It did this before, rained a bunch and then was fine for about 6 weeks.  Now it's back.  Rain is probably just a weird coincidence.  However, when I checked the bulb on the brake light above the rear window, I noticed that the wiring runs independently of the rear tail light, so I'm assuming the problem is at the front of the truck.  However, I don't know where all of that connects or if there's a relay or anything else  I can check other than the fuses.