Its not uncommon for an owner or trailer shop to decide, "Oh, I've got the wrong plug on the vehicle, I'll change it to the one the setup requires," instead of adding a plug or otherwise wiring in a flexible way.
I use a 7-to-4 pin adapter
in the toad to preclude feedback into the toad wiring. I believe there are also 7-to-6 adapters
That said, I'm guessing Foster's rig came w/7-pin and was wired to 6 pin, and now the converter module is fried. Modules are obtainable at NAPA, AutoZone, etc., and you may find one that has the exact same wiring for more or less plug & play. This is one area I'd spend the extra coupla bucks for heat-shrink-sealing connectors as it is a wet condition of use area.
You can diagnose the wiring into the module to see if the signal still exists there (I'm guessing yes as all
your toad lights appear to be out, not just stop or turn, etc.). This is where a Power Probe 3
will do the job in about 3 minutes using the piercing probes; IIWMI'd seal the pierce holes on completion, or do the pierces where I'd do the cut/splice for the new module. You can do the same w/a decent test light & a good piercing probe for any circuits that light, but a ground circuit won't tell you much w/the trouble light and the PP3 will (it reads ground & has a low tone it sounds, high tone for batt voltage, and volt meter readout to get actual voltage so you can read volt drop).
This has NOT been a paid announcement by a celebrity.