No Running Lights

Not being an electrician this one has me stumped.  The 12 volt at the Bargman plug is hot.  I have both left and right turn signals and brake lights functioning on TV and my pod.  But, if I turn on the running lights, all okay on the TV but nothing on the pod.  The plug appears fine, cannot find any fuses shorted out, so where do I go from here?  Thanks.

I had the same trouble a year or so ago.  Very hard to see, but it was, as Stephen suggests, a bent terminal in the trailer side of the Bargman. I aligned the connectors and scraped them with a knife.  A point file might have been better.  WD40 will work, but there are specialty sprays for electrical connections.

TT

Thank you all for the pointers and advice!  I ended up taking it to a local auto repair and the mechanic was able to diagnose the problem in about 15 minutes.  Turns out to be a powered 10 amp tail light converter located between the upper part of my bumper and inside the back lower portion of the rear end of my Explorer.  The worst part was to access the converter, took him about 30 minutes to remove all the plastic garbage to gain access.  This  2.5" x 4" box  has 4 wires running into it and 6 coming out.  Inside the box all the wiring is encased in poured plastic with 3 relay/fuses between the 4 wires in and 6 wires out.  I will tear this apart and see where the problem lies but the only way to fix is to purchase a new unit and have the mechanic install.  Again thank you all for your advice!  Much appreciated.