SOhappy

Background: I pull a variety of trailers, some of which I don't own and have no idea if the lights are shorted-out or not. Now I have a trailer-light problem: There's no juice to the right turn/brake pin on the trailer connector. Checked continuity all the way back to pin 7 of connector 1 on the PDC, it's good. I don't have continuity to the inside pin on fuse 47. Although the relay is clicking, I'm guessing the relay is bad or a circuit board trace is blown. I suppose it could also be the control circuit coming from the FCM (pin 34). Haven't figured out how to test that one yet , got to do some head scratching.

Problem is, if it's the relay...well it's internal to the PDC (even though there are five or six empty "spare" external relay ports on the PDC ).
I'm thinking about opening the black box to replace it, and want to hear from anyone else who's tried it. Or, has anyone found a way to hack a new circuit to the trailer connector? It's probably not as simple as splicing into the truck's tail lights since that circuit is sensitive to variations in current (manifested by the annoying "lamp out" dashboard light).

I don't want to hear from the "that's not a very good idea" crowd. I figure I've got nothing to loose. A new PDC is $400.