On the HD w/trailering it's blunt cut after extenting from IP relay block.
That's the same place the Hi-Stop is wired (splice point)
You may want to see if you can get it from there.
If you're up to some fun with IDing connectors...
it's "D" on C7, where the colors are blk, brn, DkBlu, red, LtBlu
Not to be confused with same colors coming in on C1
or Hi-Stop LtBlu exiting on "J" of C3.
But let's not make this a color thing.