Trailer running lights don't turn on right away

[ToyHaulin]

So I replaced the plug on my boat trailer to a 7-blade connector having previously been a 5-flat plug. I soldered the new 7-blade to the existing trailer wiring. What I have noticed is the trailer's running lights don't always turn on the first time after it's connected. My 2020 RAM 1500 doesn't seem to sense the trailer is connected right away. Once the lights come on they work reliably and predictably... shutting off when I park and turning back on when the sun sets. This behavior never happened with the 5-flat connector which I had been using with a 7-blade to 5-flat adapter. The trailer has exactly the same wiring and lights as it always had before the new plug was soldered in place.

 

[crash68]

I'm guessing it's possibly a problem with the plug you installed. The only wire that would have any sensing would be the trailer brake wire, the others should just be driven by relay contacts.

 

[Green_Manalishi]

I have the same problem and attribute it to an improper ground. Once I start rolling, the trailer grounds through the ball and the lights work fine.