Hello all, first time poster.

I found this older thread here which had some helpful information on how to wire the 3rd brake light for a truck cap.

However, I'm still fuzzy on some details and was looking for some help.

1. Location of the CHMSL wire that is under the dash. I looked under there but did not know what to look for. Google searches and forum searches never seem to give a good frame of reference.
2. Wires. My truck cap was a used cap with the wires cut. There is one red wire and one black wire. Am I to assume the red is hot and black is ground?
3. My plan was to locate the CHMSL wire, attach a fuse connector there with a 5 amp fuse (per the suggestions in the linked thread), run a loomed wire under the frame of the truck, to the bed, probably going up through the taillight housing. From there I connect the truck cap to the truck with a male/female plug of some kind, in order to be able to remove the cap in the future.

If anyone can give me some help or confirm my plan is sound, that would be great. Thank you in advance.