Help with Electrical Problem

[Already Gone]

I am changing over from my step to a new sport bumper. As you can see in the pic the po had installed a set of running lights just above the bumper. When I started to check things out and undo the wiring yesyerday it looked straight forward. Those running lights were wired along with the license plate lights so that when you put on your park or headlites they came on. There was also a big ground strap from one of the bumper brackest to a bolt in the bar the running lights were on. I found the positive wire coming out of the factory tail/brake running light harness which the po had used to power the running lights and license lights. So I disconnected all the running lights and license lights left the ground strap intact. I thought I'd make sure I had power and when I pulled my park lights on I had no taillights /brake lights or factory running lights on the truck and when I checked with the test light I have no power from the wire that was powering the rear running lights and license lights. Anyone got any ideas what could be wrong? I'm thinking some kind of ground problem