Help needed with wiring camper shell taillight

I bought a used camper shell off a guy on Craigslist. Now I'm having trouble wiring the high back third taillight to my brake light system.

As you can see from the picture, the camper shell has a existing wiring harness. It doesn't fit into any obvious place on my taillight assembly.

It looks similar to the four pin harness for a trailer hitch. But my existing four pin trailer harnesses won't fit.

Any suggestions on how to proceed?

 

You are missing the other half of the wire harness. There is a male connector that gets wired into your break light. Then you can disconnect the wire harness to pull the cap off.

 

I’m guessing you have an overhead dome light as well? My camper shell had something similar. I figured out which two powered the brake light and then tapped those into my trucks brake light.

 

When I rewired mine I tapped into the break light for the 3rd brake light and the red running light for the inner light

 

so this is my first camper shell and I've never done this. Is there a standard wiring harness or way to do this?
I've been Googling around to find an appropriate harness to buy, but I can't find one.

BTW, I do not have a dome light on the camper. So this is just for the brake light.

 

I can try and walk you through it then. How many wires are going into that plug on the camper shell?

 

I have 4 wires. See pic

 

Are you positive there's no dome light anywhere in there? There's no reason to have more than two wires for a brake light.

Another question before we get started, do you plan on taking off the camper shell or is it "permanently" attached to your truck?

 

There isn't a dome light. On the backside of the high back taillight there appears to be a place that may be a light. But there isn't an obvious on / off switch for that potential light. So I don't know how it would be controlled

Edit. I was hoping to be able to take the shell off for the summer time. So I prefer not to permanently wire it in.

 

Ah, yep. That's what the other two wires are for. There's a switch on there somewhere, if not obvious.

So back to my other question. Do you plan on removing this shell at all or will this be permanently on there?

 

I prefer to be able to remove it for the summer time.

 

So the first step is to cut off that plug, and strip a little insulation back on each wire. Then you’ll want to use a drill battery (or a 9v battery) and use trial and error to figure out which two wires are for the brake light.

 

Bestgle 60 Pcs/30 Pairs Self-Stripping Electrical T-Tap Wire Spade Connectors Set Quick Splice Wire Terminals and Fully Insulated Male Butt Terminal Crimp Assortment Kits (Yellow, Red and Blue)

https://www.amazon.com/dp/B01N6EKSGK/ref=cm_sw_r_cp_api_rV-wAb935HDNC

You’ll basically use these to tap into the brake light, and be able to disconnect it come summer time.

 

Thanks. I will roll over to Lowe's tomorrow and get some. Ping you back when I have them.

 

Sounds good. It’s not a hard install as long as you have a couple basic electrical tools. If you don’t have any, get one of these. It’s not the best but it gets the job done.

 

I wouldn't use those no matter what. Those things always cause tons of corrosion problem later on down the road. Just get some butt connects and cut and Crip and seal with shrink wrap. I swapped my plugs to a 4 pin trailer connectors so I can cover them when my cap is off too.

 

Just a matter of personal opinion I guess. I’ve used these quite a bit and for long periods of times and never had a problem with them.

 

I mean they work great but from what I've seen from working on over the road trucks is that they let in lots of corrosion especially where roads are salted

 

I don't remember now what I used for connectors, but I tapped into the brake light on the left side of the truck and sealed the connections afterward with good quality 3M electrical tape, followed with a light coat of silicone over the tape. That was 8 years ago, and I've not had any problems. I tapped into the harness that stays with the tail light after the factory disconnect plug is disconnected, that way if there ever was a problem it would be with the easily replaced part of the harness, not with the main harness that stays with the truck, if that makes sense.

I ran a wire up the the cab and to the fuse block behind the coin tray and then used an add a fuse to connect power for the dome light, that way it works anytime. I don't know why people tap into the tail light circuit for the dome light, that would drive me nuts having to have the tails on just for light in the camper.