When I bought the truck used, one perplexing thing was the lack of a towing receptacle in the rear for a trailer electrical hook-up. The truck had the whole towing package including transmission cooler, 2" hitch receiver, it even had an electric brake controller... so where the heck was the connector???
It turns out that the 7-pin connector was lying on top of the spare tire. It was in pretty rough shape. The center connector was so loose it was amazing it had not fallen out. The adjacent 4-flat connector was totally exposed and weathered. The ground post had fallen completely off.
I thoroughly cleaned, tightened and straightened out the 7-pin connector. I tested it (as much as I could) and it appears to be in working order!
I bought a bunch of 4-flat and other wire including some 12GA black & red. I made a new plug that would go into the 7-pin jack with two separate harnesses coming out for routing into the topper shell:
-4-flat (ground, tail, left/brake, right/brake) plus back-up lights
-black & red 12GA for AUX power
I also snipped the bad 4-flat that was adjacent to the 7-pin jack. Spliced it and ran a clean 4-flat extension to a new clean plug with rubber boot and mounted it next to the hitch receiver by way of a clamp with rubber grommet protector. So, I have a nice 4-flat if I ever need it. I can still use the 7-pin for towing as well, I'd just have to disconnect the new harness(es) mentioned above which now feed the interior of the topper.
So, I took the 12GA black & red now energized with 12V AUX power when the truck is running and routed them back near my main power center on the passenger side toward the front of the bed. I put a fuse holder and 20A fuse in-line. I had a 3-outlet cigarette plug with heavy gauge wire laying around so decided to use it. It has LED illumination when energized. I did not want to drill holes in the bed so I used a heavy duty magnet and bolted a piece of walnut to it. Then lagged the outlet onto it:
(the red & black wires on the left are 16GA for a dome light BTW; not part of this outlet)
Now, I still maintain completely discrete power systems. However, having truck AUX 12VDC power opens up some options...
1) I have back-up power if the solar system experiences a failure for some reason.
2) I can run things that aren't quite right for the solar power such as a fan for the dog when it's hot... or a heater for the dog if it's freezing cold...
3) I could potentially set up a way to charge the system off the truck while driving; this has not been a need heretofore but I suppose if I go someplace that isn't as sunny as Colorado (say, Alaska) that could become a need
In an upcoming post I'll show you what I am doing with the other trailer wires now routed into the topper.