Since last summer, I've been battling an intermittent trailer light issue. Last summer I was able to sand off the metal bits of the plug and receptacle which seemed to remove the corrosion allowing the lights to work.
On Saturday morning, my brake lights and running lights worked great. When I loaded up on Sunday morning, none of the running lights worked, but I did have brake lights and blinkers. I went to the show anyway as running lights only come on when the headlights are on.
After an hour of sandpapering and climbing in and out of the truck bed to check the lights, I had only made the problem worse! None of the trailer lights were working, not even the brake lights. I'll admit to using a few choice words, most of which began with the letter "F."
The ranch owners are quite handy with vehicle issues, so I hunted them down and asked for some advice. It was agreed upon by all (why I contributed to the conversation I don't know as I clearly couldn't fix it) that I should take the truck and trailer in to have it repaired professionally.