Trailer lights questions

[Sam4msu]

i have a 17 Expedition Limited and my utility trailer lights don’t work right when plugged into the 7 pin receptacle. Whenever I turn either blinker on they both flash and I get a bulb error. Other trailers work fine on that truck and the cargo trailer works fine on other trucks. Any ideas?

 

[USMCBuckWild]

There are actually 3 different 7 pin wiring pin-outs. Can’t recall the names of them all off the top of my head. Found out when I was reairing my trailer for 7pin/4pin.

I would do a quick check of the pin-out on the trailer with a 9 volt battery. If it checks out....... poor ground connection?