I have had problems with these plugs on my 2001. 5 and the same thing on my 2003. I have three different trailers, each with their own plug. On several occasions when I plug it in, different lights radomly won't work. I finally figured out that sometimes when pushing the male plug in, one or more of the pins doesn't engage squarely in the female sockets and will push the pin back into the plug instead of into the prongs of the female socket. Sometimes it's one pin, sometimes two, sometimes none. So I always have to check my trailers after hooking to make sure all the lights work. If you know what pins are what, look into the end of the male plug and make sure one of those pins didn't get pushed back down into the plug and not making connection. If a pin does get shoved back in the plug, I tap the flat end of the plug on something firm, like the trailer frame and it will make the pin come back down into a position where it makes connection. I know this sounds like a jackleg operation, but that's what I do. Like I said, two different Dodges, three different trailers with individual plugs. I've had every one of them do it. I have tried spreading the prongs a little inside the female socket on the truck to reduce the resistance, but I never did any good trying that. May not be your problem, but it sounds similar to my experiences.