I have a 2006 Dodge 2500 CTD. My left trailer blinker and brake light do not work, on my 4 pin and 7 pin hook up. My left signal and brake light work on the truck. I used a test light and traced the yellow wire back to the fire wall of the truck and the wire tests bad. Where does this tie into? Where is the flasher located? Could it be bad? All fuses are good. Any help would be apprecitated.

 

I have an 04 Ram with the same left light issue. I unbolted my fuse panel to find that the yellow wire plug underneath into the center of a blue wire harness. There was no power/signal from the fuse panel/Integrated power module to the yellow wire.The flasher seems to be encased inside the fuse panel.
This problem got no remedy from the dealer nor uhaul other than being told it is common.
Will do more checking into the Integrated Power Model :vender code 16238AC
Best of Luck