I finally got around to hooking up my trailer to my new 92 F250. I had to install a new 7 pin connector because the truck came with a 7 pin round and I needed the 7 flat. All my lights work but both the left and right turn signals flash very rapidly, if I unplug the connector the lights on the truck flash normally. Also when the headlights are on and I step on the brake pedal, the brake lights are very faint. With the headlights off the brake lights work good. When I unplug the connector the truck acts the same with the headlights on the brake lights are very faint. Could my brake light switch need adjusted? Any other ideas? Thanks

 

dont think there are any adjustments on the switch.the fast flashing is easy to fix. go to your local parts store and buy a new heavy duty flasher for towing. as for the dim lighting issue i would start where that trailer hook up is wired into the truck harness. lots of areas for corrosion and loose connections.

 

I agree you need a heavy duty or electronic flasher module. I have had the same problem with just hooking up my 4 pin connector to a trailer.