Rooftop Tents blocking brake lights (CHMSL)

[strykerwsu]

What height is your rack? I keep going back and forth on keeping the tent low, going mid height, or going full height to the rooftop bar height.

21 inches from the top of bed. About 1 inch base, 19 inch sides and 1 inch top, with 2.5 spacers on top to clear fin. Likely could reduce to 18 inch sides but may start to impact 3rd light but would be a little more flush. I'm taking rack off with tent so will never run silo but those who do might want a more flush rack to cab height. I have an extra 1+ inch over fin so likely will reduce spacers by an inch. I get into 8 foot garage but it is close in All Purpose with 21s (33). Afraid once put on 20's (34) may have to go to sport and will forget lol.

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[fergie]

What height is your rack? I keep going back and forth on keeping the tent low, going mid height, or going full height to the rooftop bar height.

Thanks for sharing. Do you have a side view photo?

 

[avigneault]

Got the third brake light working, but with one caveat: since there is no distinct wire controlling brake (vs signal), my center mounted light flashes if the indicator is enabled and the brakes are not pressed. I think I'm fine with this, but it's moderately irritating.

Control module is mounted up on the aluminum crush member in the rear bumper. This must be as close to the driver's side of the truck as possible so as to allow the sensor to reach the tail light loom without conflicting with the tailgate piston kinematics.

I followed @Dark-Fx and routed 12v power from a tap in the gear tunnel. It is extremely important to locate an inline fuse someplace accessible, as you'll need to pull it occasionally while setting up. After realizing this and pulling the skid plates off 3 times (!), I moved it here:

Next to the harness below the lower gear tunnel trim panel.

 

[Dark-Fx]

Got the third brake light working, but with one caveat: since there is no distinct wire controlling brake (vs signal), my center mounted light flashes if the indicator is enabled and the brakes are not pressed. I think I'm fine with this, but it's moderately irritating.

Control module is mounted up on the aluminum crush member in the rear bumper. This must be as close to the driver's side of the truck as possible so as to allow the sensor to reach the tail light loom without conflicting with the tailgate piston kinematics.

I followed @Dark-Fx and routed 12v power from a tap in the gear tunnel. It is extremely important to locate an inline fuse someplace accessible, as you'll need to pull it occasionally while setting up. After realizing this and pulling the skid plates off 3 times (!), I moved it here:

Next to the harness below the lower gear tunnel trim panel.

I think there are signal isolators you could get to put between the controller and the light. I'm not using one since my light bar expects left and right signals normally anyway.

 

[avigneault]

So here's the thing: I suspect a 2-to-3 converter is the only device necessary to pull off this install. Will you have to tap wires? Yes, but you're going to need to tap for 12 volt anyway.

Pull the left signal/brake from the left black wire going to the tail light, and the right turn/brake from the right black tail light wire. Ground the white wire to the frame. The 2-to-3 converter will resolve separate brake and turn signal wires. If you only need the brake signal, cap the turn signal wires.

Saves you $120, a days' worth of work, and running 12v all the way to the gear tunnel.

 

[Riviot]

Dumb question, a quick DuckDuckGo didn't answer it:

Are there OBD-II connected wireless brake lights? Plug-in or battery powered, but the braking on/off comes from the plug?

 

[jjswan33]

my center mounted light flashes if the indicator is enabled and the brakes are not pressed

I’m not sure what you mean here?

 

[Dark-Fx]

I’m not sure what you mean here?

It's picking up the turn signal. If the light isn't intentionally being used that way it needs an isolator/converter like one of these: https://www.amazon.com/RED-WOLF-Converter-Connector-Separate/dp/B07Z5Z8BZ7

I have no affiliation with that product and have never used it, just the first thing that came up in a search.

 

[jjswan33]

It's picking up the turn signal. If the light isn't intentionally being used that way it needs an isolator/converter like one of these: https://www.amazon.com/RED-WOLF-Converter-Connector-Separate/dp/B07Z5Z8BZ7

I have no affiliation with that product and have never used it, just the first thing that came up in a search.

Got it. I’ll need to go over this thread more carefully. They installed a brake light on my shell so I’m left with 2 choices, make it work or remove it because I think having a non-functioning brake light is worse than not having one…

 

[Dark-Fx]

Got it. I’ll need to go over this thread more carefully. They installed a brake light on my shell so I’m left with 2 choices, make it work or remove it because I think having a non-functioning brake light is worse than not having one…

You could investigate wiring a jumper in from the CHMSL in the spoiler. That wiring has to be accessible from inside the truck somewhere, but I haven't pulled any interior panels out of my truck yet,.

 

[avigneault]

You could investigate wiring a jumper in from the CHMSL in the spoiler. That wiring has to be accessible from inside the truck somewhere, but I haven't pulled any interior panels out of my truck yet,.

I recommend against this, the spoiler is held together with plastic clips and adhesive. Disassembly = destruction.

 

[Dark-Fx]

I recommend against this, the spoiler is held together with plastic clips and adhesive. Disassembly = destruction.

That's why I suggested from inside the truck, not actually pulling the spoiler apart.

 

[avigneault]

I’m not sure what you mean here?

My system (currently) is just the left and right brake light tied together. So whatever one or both of them are doing is reflected in the light. If brakes are pressed, center light is solid. If indicating, center light is flashing. If brakes pressed and also indicating, center light is solid.

This isn't ideal. Using a device like https://www.amazon.com/CURT-56196-2-to-3-Wire-Taillight-Converter/dp/B0046EKPHY/ref=sr_1_5?crid=RREE13PAZYN2&keywords=2-to-3+wire+converter&qid=1680853473&sprefix=2-to-3+wire+converter,aps,102&sr=8-5 should result in a brake wire that only ignites when brakes are pressed, not when indicating.

The Tekonsha (119250) device may not be necessary and, indeed, potentially more intrusive.

 

[avigneault]

That's why I suggested from inside the truck, not actually pulling the spoiler apart.

Not sure if pulling interior panels or the headliner is a much better option

 

[jjswan33]

Not sure if pulling interior panels or the headliner is a much better option

I mean presumably the light is changeable without major reconstruction but who knows.

I’ll have to think through this, I have 12V in the bed available so at least that part is easy.

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