I have a 7 Way Round Trailer Connector on my bumper and if i look under the bumper i see that there is a 4 pin connector there as well which is fully functional. My problem is...the 7 Way Round Trailer Connector is not plugged in....where can i find the male end? Should there be a male end under the truck somewhere or do i need to buy something?

On a side note...When i use the 4 pin connector for my trailer the parking lights don't work...but everything else does...is this a trailer issue or truck issue?

Thank you all for your input.