Ths regards the + wire that sends power to the aux pin, which is used for the hot wire and to charge the battery on a trailer.
Mine was found to be bad on vacaton. The result was that the trailer batteries were not being charged between stops.
Took it to the dealer (only been selling GM GM trucks for two months), and said that if I needed power, I had to put a fuse in STUD#1. The owners manual says that if you have the dual battery option (04 GC D/A)not to put a fuse in that slot. Dealer said that sometimes the owners manuals are not printed correctly. He installed a fuse and everything seems to be OK. Am I missing something here? I am sure that it worked when I got the trailer controller hooked up (Prodigy)

What gives?

All diesels need the fuse. The manual is confusing but it is talking about gas engine trucks. Your good to go.

:exactly: Refers to dual battery option on gas versions.

Yeah, I would not call it incorrect - just poorly worded. It reads -

"Auxiliary power (Single Battery and Diesel only)/Dual battery (TP2) Do not install fuse"

What that means is any single battery gas, single battery diesel, or dual battery diesel can install the fuse. The only ones who should not install the fuse is a dual battery gas engine (TP2).

Again, not very user friendly. But this question comes up a lot (probably once a week or so) so there are quite a few threads around if you want to do some more reading.

They also give you a fuse for it wrapped up in the trailer brake wiring harness. 40 amp.

In any case, I am glad you got it working. Take care~