2012 Columbia, no trailer signals

Yes, rear tractor signals work. As I said I rigged it from the side fairing signals into the 7way cord to get thru. I have more tools etc at my shop at home. At that point I'll go from back to front and follow the dead wire back, connector by connector until I find power.
I'm still confused why when I was in the PDM on the b pillar, why the signals started flashing? When I move that again, they stopped?
I hope to be home next week and have some time to get to the bottom of it.
Thanks again for all your help.

 

So... finally got home, picked up the PDM at my dealer and put it in. I attached my test light and had the wife throw the signal lights on and at first they didnt flash, then it blinked erratically for a second and fell in lock step with the truck flashers.
I still wanted to know why, so I removed all the fuses one by one and it didnt effect the trailer signals at all. I unplugged the plugs (2 top 2 side 2 bottom) from the PCM and the weirdness started.
With the pcm unplugged, ANY signal light right or left gets all signals on like 4 ways? But the side signals were very faint. The green plug on the side seemed to be the one that really triggered this. Plug everything back in and signals ALL work perfectly. So somehow the signals are passing thru the PCM but not fused there?
And no labels saying signals?
Anyway, it works and I'm happy.
Thanks for all the help!!!