Leer Cap Wiring - SNO BUS Style

I have a Leer cap on my '18 Limited, installed by a local dealer. I have a few options: extra dome light, carpet, 3 12v outlets, and keyless entry. The wiring that came with it is pretty ok, and it would have been better if the dealer hadn't done a quick and dirty wiring job. Wires loosely dangling along the frame, poor crimps, lazy wire organization, etc. The stock Leer wiring is a little junction box designed to be able to be easily unplugged if the owner wants to remove the cap, but very cumbersome if an electrical component of the cap needs to be replaced. In an effort to remedy the lazy installation and be able to both service components easily and remove the cap easily, I set out to design my own wiring. This is the box that comes with the Leer:



The basic idea is that everything is grounded to one place (in my case, the installer grounded it to my brake light's 18-gauge ground wire, not a good idea imo) and then the 12v outlets and dome lights were fused and wired to the positive terminal. The third brake light is tapped into a main brake light wire and the keyless entry (2 wires, one lock, one unlock) are tapped into the respective wires for the driver's door in the kick panel. Here's a snippet of what the dome light and 12v outlet wiring looked like in the engine bay:



Two different kinds of fuse holders, no thought put into wire routing from the frame to here, just not clean and to my standards. My solution for this area was a couple of things: I got a mini fuse tap for the dome light fuse, and tapped into the factory fuse for the truck bed light in the factory 3rd brake light assembly. Keeps the original 7.5A fuse intact, and I added a 2A fuse (5A pictured) for the dome lights. For the 12v outlets, I added a small Blue Sea 4-circuit fuse box with a 6ga wire running to it from the positive post. I plan to wire a lightbar and possibly other things in the future, so this is a good system. I wired the 12v outlets to here with a 15a fuse, and then ran the 12v outlet wire and dome light wires more thoughtfully back to the factory harness at the firewall and down to the frame.



I kept the dealer wiring intact for the keyless entry, as the taps were done correctly and were hidden from sight. I tried some 2a fuses for fun, as I had them laying around, but this is a bad idea. Stick with 5a fuses here.



I completely forget how these wires make it outside of the cab and along the frame, I believe they are slipped through a little grommet in the floor pan and joins up with the 12v outlet and dome light wiring. I did my best to secure all this wiring to the frame, as it wasn’t secured at all before.



The wires run up from the frame to behind the left tail light. The third brake light wiring is easy, it’s just tapped into the left brake light’s 12v power and fused (shown here disconnected from the tap)



This wiring goes up through a hole in the bed, which brings us to fun part: replacement of the original junction box thingy. I opted to go for a simple Blue Sea 6 circuit terminal block that would accept ring-terminated wiring for easy removal and maintenance (I’m glad I did this, as I had to replace my third brake light shortly after). I had to play around and extend some wires, but it works very well. I moved the ground from the brake light ground to a chassis ground on the bed behind the brake light, with a thicker (12ga) yellow wire seen above.




I topped it off with zip ties and electrical tape and wire loom to make it pretty. The first circuit is the third brake light, second is the two dome lights, third and fourth is for the lock on the cap, fifth is 12v for the 12v outlets, and sixth is the ground for everything. This system works great and is easier and cleaner than the Leer one imo. What I wish I had done differently was in dealing with the grounds, as I crimped all 4 grounds into one ring terminal, so I would have had to re do that crimp if I has to replace only one thing, which would be a pain because then I wouldn’t have enough wire. When I replaced my third brake light, I took advantage of my system for the 12v portion by simply unscrewing it, but then had to use a butt connector on the new brake light’s ground and connect it to the already established ground from the old brake light, which worked fine as it is concealed by wire loom by the dome light, but it’s something to keep in mind. I wasn’t worried about losing the fuses in the OEM electrical box thingy, as all my circuits were already fused elsewhere.

Let me know if I missed anything, if anyone has any questions, criticisms, whatever. If anyone needs wiring help for jobs like these, feel free to DM me, I know the electrical of these caps inside and out and have done automotive electrical for years.

 

No feed back on a nice informative post....ashame. I'm no expert so I was hoping for some constructive comments, so I can do my cap.

 

Fwiw, no problems at all since doing it. Wouldnt have done anything differently.

 

I would make one recommendation.
The wires that are tapped behind the kick panel and are run through the floor. Check how they were run. The wiring on both my truck and my father's truck were not run through the grommet. Instead, they pulled the grommet out, ran the wire through the hole, then put the grommet back. This put the wiring in a direct contact pinch with the edge of the sheet metal. I had to pull the grommet out, slit it, and put it back with the wires in the middle and turn it so the split was on the opposite side of where the wires enter. Then I put some tape over the slit side of the grommet to ensure it stays in place and tight.

 

Does your truck have the locking tailgate? Anyway to tie in the keyless to the tailgate keyless option?

 

nice job! I will be doing the same shortly! Only difference is I like using the Posi-taps.