Could even be your truck connector. I have both the bumper 7 pin connector and the in-bed 7 pin connector. Sometimes the cord to the in-bed connector does not make contact well on my 5er running lights and I have to push and wiggle to get the lights to work. But once they do, they are good til the next time. When they may or may not connect. Sometimes I use the in-bed and sometimes the bumper, and I never have the problem with the 5er connected to the bumper connector. Looking inside both the bumper and in-bed connectors, I can see no obvious difference. And like you, I have tried the screwdriver to the pins routine.
