rcowan wrote:Thanks for the replies. Sorry for such a late response myself but I couldn't log in for a while for some reason. I'm back now though!
It was the switch. I replaced it and I've been fine now on quite a few more trips with the trailer. Thanks again!
if you run your trailer lights through a relay instead of directly through the truck's wiring, it could save you another switch. I noticed on the bumpside Ford trucks, when hauling a trailer, the same thing would happen, I used a relay and ran an independant harness for the trailer lights and Electric brake control, and problem dissappeared. mounted everything on the L inner fender close to the firewall. I got a 4 wire insulated bundle from our local truck parts place. 3 lighter guage wires for the lites and one heavier for the electric brakes. I didn't use a relay for the signals because trailer only adds 1 bulb each side , but trailer brake relay and marker/tail lite were installed.
no point in overloading any of that old wiring!
I also had a problem with the headlites going out on highbeams in the 72 Bronco so I ran them on a relay instead of direct, that problem dissappeared too. the replacement Halogen bulbs pull more amps than the old lights too!
summer:RIP 68 Merc, 72 Bronc.
winter> wife: 94 explorer xlt, mine: Barney the powerstroke clubwagon
projects: 93 Bronco 7.3 powerstroke, 70 F250 crewcab 5.9cummins/ZF 4wd
67 Mercury700 on 98 F800 chassis, 91 C350 4x4 diesel Centurion.
compression ignition rules!!