[tower]

I may have figured it out. I think if I don't connect a ground, it might work. If I connect one lead of the HI to the flashers and the other to the brake, it can pull ground through the non-working filaments. I will test and post. I wish I could say that I came up with this notion on my own, but I was inspired by something I read from Daniel stern. I was thinking about tapping into the marker lights, when I came upon this:

LINK