It's done already. New BCM fixed it. Perhaps I could have gotten a salvage BCM, but would have had to pay dealer to reprogram it? And "all sales final" on salvage electronics. Seems to be a bit of conflicting information out there, hard to sort it all out in a reasonable amount of time. I couldn't keep driving without a blinker, but thanks for the advice anyway.

 

Any newer vehicle that has it's lights driven by a BCM should have a T(one)-connector installed to power the trailer lights.
That way the BCM will not be damaged by faulty trailer lamps/wiring.

if you screw up the BCM not only won't your trailer lights work but the van lights won't work either.

With a T(one)-connecter you can blow the fuse on the T0ne (lose your trailer lights) but the van itself is still good.