I just tapped the stock back-up light wiring near the harness connector on the rear of the driverside frame rail. The stock wiring is plenty heavy enough for the light that I added. (I know that scotch lock taps are a "no-no" heat shrink and solder are a much better solution. Do as I preach, not as I do.)
The hole I had left over after raising my hitch and adding recovery hooks worked pretty good for mounting the light. It is just a small implement light, but works great.
If you are adding more than the small light that I added , a relay would be a good idea. It can be activated by the same wire that I used. I would mount a relay inside the rear frame rail near the tail light wiring.
Tractor supply rubber housing lights with a integrated bulb reflector work really well. You choose flood or spot.
NAPA Online page
Item#: BK 7355799
Price: $15.99
Attributes:
Manufacturer
ilot Automotive
Style Name:Rubber Housing Utility Light
Material:Rubber
Dimensions:4"
Color:Black
Installation Type:to Bracket to Vehicle
Package Contents:Light Brackets Installation Hardware & Instructions
Those are sealed beam bulbs. They just pop out of that rubber housing.
That is what I have on my old S-10. If those flood lamp bulbs do not offer enough light, there is an aircraft landing light bulb that fits right in that rubber housing. They really are durable. They one I have on my old S-10 has been in service for over a decade.
It is switch operated, so that may have something to do with the hours of operation. I prefer the way my current truck is wired though. Several times I forgot that I had flipped the switch and drove around with the back-up light on. Having it come on with the back-up lights is a better idea. Heck the parking lots are where you need it most.
My one light plus the 50w halogen back up light replacement bulbs are ok. Not daylight , and not as much as I had on my old truck, but pretty good. If I need some serious light I attach my winch and the remote controlled lights to the rear.
I only added one light. Keep in mind that the drivers side is all you really need most of the time. If your window tint is really dark, the passenger side mirror doesn't do much for you when it is dark outside.
If you are down to one lamp and the wattage is low enough, tapping the wiring for that light and not using a relay may work. If the draw is too much you pop the fuse. Mine have been working fine for quite a long time now.