# Third Brake Light Wire Location?



## Insomniak

Well, I went and did it! Traded in my 2012 Ram for a new 2013 Ram with all the new bells and whistles. More on that later. I kept my Snug Top bed shell, and put it on the new truck last week. We fiddled around the rear of the truck looking for a wire stub sticking out of the harness for the shell's brake light, but couldn't find one. The 2012 Ram had (apparently, unless somebody added it) a wire with a plastic coated end that the shell wire was spliced into. We ended up removing the left rear tail light assembly and found a wire that lit up on the multimeter when the brakes were applied, so we tapped into that. Oops, what we didn't notice was that the shell brake light also flashes when the left turn signal is on! Is there a way for me to tap into the 7 pin trailer connector on the bumper and use that for the brake light? There's also a 4 pin connector. I cant find a wire on either connector that lights up when the brakes are applied. HELP!!!!


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## Boomer

There should be a wire on the seven pin connection that energizes when the brakes are hit. Otherwise you would not get brake lights or trailer breaks for your trailer? Probably the 4 pin as well.

Boomer


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## RDS

The flip up lid on the trailer connector is labeled.


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## outback loft

The installer usually just taps into the brake light line with a pre made wire harness for the third brake light.


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## Insomniak

We didn't find a wire on the 7 pin connector that energized solely when the brakes were being applied. Maybe we were just in too much of a rush and need to try again. Looking at the schematic, I assumed that the lower right pin was for the trailer brakes. We figured the pins were for (starting at the 1 o'clock position): constant 12 volt, right turn signal, trailer brakes, reverse lights, ground, left turn signal, and running lights. Does the trailer umbilical need to be connected to the truck in order for power to be sent to the brakes?


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## Boomer

Attached is a typical wiring setup, which I got from a Google search. They are standard and you are correct with your pin figuring. And if you mean the trailer 7 pin plug as "Umbilical", I don't think it needs to be connected for power to be sent to the brake pin.

Edit. I see my attachment did not attach, but a google search on "7 pin trailer wiring" and you will get a ton of pics on the subject.


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## Insomniak

I tried again and we aren't getting any voltage at the brake pin at the 5:00 position when the truck brakes are applied. I'm guessing this has something to do with the brake controller and the trailer not being connected. Also, most 7 pin schematics refer to the pins in the 3:00 and 9:00 positions as "turn signal/brake". I'm getting 12 volts at those pins when the brakes are applied, but that voltage also fluctuates when the turn signal is on. Looks like I'll need to go back to the tail lamp assembly and check those wires a little more closely.


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## Boomer

Maybe the service department at the dealer might be able to help?


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## Insomniak

Found it!! I lowered the spare tire and looked everywhere for the wire stub - along the frame on both sides, up to the engine compartment and along the rear bumper. Found nothing until I ran my hand over each bit of wiring harness in the back and came upon a wire partially taped ON TOP of the harness, right against the underside of the truck bed. Bingo! That was the wire. Oooh, such a nasty thing for somebody at the factory to do! Anyway, all is wired properly and working. Here's a photo of where the little sucker was hidden:


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## jake's outback

Wow that was way to easy!







Dodge the secret is out! LOL!


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