Wiring a cap, am i wrong?

So I purchased a ARE cap a few weeks ago. I need to get it wired up for the third brake, and the interior dome. It is prewired with a 4 pin trailer plug. I plan to get the same with a pigtail to tie into it.

My question is this. I have seen quite a few people tie into the brake light wiring. I don't like that idea, and have been contemplating tying into the tow harness instead. It should have the same wiring to operate the lights. I also think I would be able to tie into it near the frame, and then take the lead i use up through the driver rear cubby. I am hoping to take in there, and then seal it with silicone. I am thinking that will allow me to keep it clean, but also keep any electrical issues isolated to the tow harness. I will be using heatshrink with low temp solder on the splices.

Has anyone tried this? If so please post some pics.

 

Bumping for response. Someone please chime in. I would like to tackle this issue in the next week or so, but would like confirmation that this is a logical way to do accomplish the install.

 

Tieing into the trailer harness wiring should work fine, I feel like there are a few people who have done that before

As for running the wires into the cap/truck the cleanest way seems to be to run them up behind the brake light and then through the small gap between the bed and the plastic rail cover. I can take a picture in a bit and post it

 

I feel more comfortable with the trailer harness, and feel like there would be more room/wire to work with.

Please post a picture of where you mean. I know a few have mentioned running the wire that way. Does it rub or is there potential to rub through the insulation? I was just thinking since i am not using the brake wires, that a different route for the wiring would be cleaner and more ideal.

 

I've thought about doing the same thing. My only concern is extra load on the trailer wiring circuit. Not that I need to be concerned about it now, but possibly in the future. To avoid this, I'd have to run the power leads all the way to the front circuit box, and if I do that, I might as well tie all the wiring in up front since the harness I got with my cap is plenty long enough for that. If I go that route, I might as well do all the wiring up front. For the brake signal wiring, I would tie into the trailer harness under the dash. For the lighting, I don't really need the lights on with the doors to the cab, so I bought a prop rod switch that I'll tie in instead of the door jamb switch circuits. I'm probably going to tackle this myself soon, I've only had the cap for 4 years. I might as well wire it up, eh?

 

I can only post my dome light setup..

 

That is a nice set up though. I thought about some LEDS on the inside of my windoors since they are solid panel. That way they would light up outside as well when opened. I'm going to stick with the dome that is accompanied to the 3rd brake light for now. I am pretty damn interested in your spare tire mount though.

 

Thanks! I have some "landing" lights on my roof rack for the area surrounding the rig:



For the tire mount, I just made this from parts I had laying around the house and some threaded rod. Cost me maybe $10 and some time in the garage. To lock it, I used a cable lock through the center of the wheel and locked it to a d-ring I installed on the bed bolt nearest the cab.

 

If your 3rd brake is LED, then the current draw won’t be much whether you decide to tie into the tail or trailer harness. That is only for your brake light though, you’d have to run another wire from elsewhere for the dome lights unless you want power to them only while your parking lights are on.

When I installed my cap I also tied into the tail light and ran my pigtail up behind it and through a hole under the top bed rail. When not in use I simply tucked the connector up into there. Different truck, but you may want to consider a similar placement so you don’t have to seal any compartments.

 

I do have plans of adding a roof rack and cab rack, but I am focusing on armor for the time being. Thanks for sharing the pics of the tire mount. I think this looks like a pretty decent winter project. I should take the stocker down and remove it at some point to get a full size spare. Until i wheel it really isn't a big deal unless i blow a sidewall. I don't do any serious rock or shale wheeling though. Just hunting and logging roads for now.

 

I don't have LED. I have considered the dome light a few times. I keep going back and forth, but ultimately I think I am going to run a dedicated power wire and inline fuse for it. At least my limited knowledge tells me there should be a fuse in the mix somewhere.

 

I just wired mine up the other day. I went to the brake light on the passenger side due to the way the wiring came down in the canopy. Double check your trailer harness. I'm not positive, but you might not have a brake light wire for the trailer. IIRC, the plug on the back has a pin for an electric brake but you need to have a brake controller for this to work. To activate the trailer brake lights the truck turns on both turn signal lights at the same time. There are modules that are available to make this work (https://www.etrailer.com/search/Brake+Turn+Light+Converter), but by that would require you to tie into both turn signal lights on the trailer harness. At that point you're getting into the realm of more complexity for not much gain. Also, most trailer canopies come with the scotchlock wire clip things. I don't recommend those if you plan on seeing dirt or rough roads. I've had better luck with butt connectors, a proper crimping tool, and the heat shrink tubing that has the glue inside.

 

Wired mine up from the brake light. Had plenty of room. I’ve done 3 trucks that were all different brands and no problems.

 

Not the greatest photos but here is where I ran the wires. I cut a notch in the plastic for more clearance but it's not necessary.



As for the actual wiring, I stole a t connector from a universal trailer wiring harness so I didn't have to cut or splice and of the factory harness.

 

Thanks for the updates and pictures. I guess I'll just have to take a better look at that area and come up with a plan.

 

At quick glance it doesn't look like there is a opening there... but it you get lower and look up underneath the rail cap you'll see it.

 

Thanks, that may be why i have overlooked it. A few people have mentioned it, but the pics i've seen show they drilled a hole and brought it out the composite bedside.