Troubleshoot no running/parking lights

I discovered I have no running/parking lights on my 2017 HRE. Thankfully, I do have brake and turns signal lights. Knowing that they are on separate circuits, I found on my 2015 Chevy Colorado a blown 20A fuse for that circuit. Replacing the fuse, I find power on that I now have power at bumper plug. Suspecting a short in the r-Pod, I put ohm meter on the trailer circuit and find 0.0 ohms leading me to believe there is a short somewhere. Inspecting everything, nothing apparent broke, cut, etc.. I inspected underneath, front driver side and see all the blocks and connections and again nothing looks damaged, but full of road dirt. I've read that the lights are LED and not bulbs and wonder if a light failure could cause the short. I looking for ideas on how best to troubleshoot the situation before taking everything apart. Thanks.

Resolved. I did a good cleaning of both sides of the 7 pin connector with cleaner and compressed air. I took my pressure sprayer and washed the undercarriage where the electrical connection blocks are (left front).  Replace the fuse on the TV and hooked the TT up. Trailer lights are now working. Putting my ohm meter on the TV trailer lights circuits yield resistance, so the short has been resolved.  Thanks @Pod People for the suggestion.