Rooftop Tents blocking brake lights (CHMSL)

[kylealden]

So, Rivian sells Yakima rooftop tents, and it seems like third-party rooftop tents are extremely popular on short-bed trucks in general (whether Thule, Yakima, iKamper, Roofnest, etc. etc. etc.).

And if I'm not mistaken, virtually 100% of these block the third brake light (CHMSL). Some people care more about this than others, but I really notice when other cars' CHMSL isn't working, and some (older) studies showed that they reduce rear-end collisions by as much as 50% compared to cars without them.

So I guess I'm curious, does anyone have (relatively clean-looking) solutions for this? Should I just not worry about it? I'm generally hesitant to tamper with even the low-voltage electrical in my truck, but maybe wiring something like this in with a quick-release plug could be an option (and then sticking the lights to the rear of the tent)? Putco® - Blade LED Tailgate Light Bar (carid.com)

Part of why this is on my mind is because the combination of a trailer hitch bike rack and a rooftop tent is going to really eat away at the visibility of the R1T's brake lights, which makes me hella nervous, especially with a years-long wait for a replacement truck and likely long lines for body work.

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[Dark-Fx]

This is something I'm planning on tackling soon too. With how small the Rivian's taillights are, I'm pretty worried about someone not seeing them.

 

[Dark-Fx]

This is what I ended up settling on. Ignore the wiring that goes to the trailer hitch area, I'm not using that now.

Bought a saris light bar meant to be put on one of their racks. Took all the bed plastics out to run wiring for another set of trailer lights. Problem is if you use the built-in set, the truck thinks you have a trailer connected, and all kinds of stuff gets disabled.

The wiring system I used is one that doesn't require breaking or cutting wires, uses an induction loop to detect current change. I looped it over the grey wires at the rear lamps, pointing away from the lights. Didn't connect anything for tail or stop lamps, just turn signals.

Wiring is routed up through the void space at the corner of the tailgate, taped down to the bedrail.

Seems to be working okay so far, but I'm curious what it will do at night. It should help with having a bike rack on the truck as well.

There is a pair of unused wiring grommets on either side of the gear tunnel wall. I used the left side and am just using the 12V outlet in the tunnel for now. I'd eventually like to run this into the fuse box, but I just wanted something serviceable for now.

 

[opnwide]

@Dark-Fx , fantastic!​

 

[AltaTruck]

This is exactly what I was looking for. I tried the route of the trailer wiring and it puts you into trailer mode. I asked service if they had another way and they would not commit to anything. Would you give as many details as possible; like more pictures, Type or link for induction coils, anything else needed for aux turn signals. I would also like running and brake since I put a motorcycle across the back with a hitch hauler and it blocks the OEM lights. Thanks.

 

[Dark-Fx]

This is exactly what I was looking for. I tried the route of the trailer wiring and it puts you into trailer mode. I asked service if they had another way and they would not commit to anything. Would you give as many details as possible; like more pictures, Type or link for induction coils, anything else needed for aux turn signals. I would also like running and brake since I put a motorcycle across the back with a hitch hauler and it blocks the OEM lights. Thanks.

I'm using a Tekonsha ZCI 4 pin system. I didn't put parking lamps on it, but should be straight forward enough to do it. Hardest part is stripping back some of the tape on the wiring to make room for the loops.

 

[avigneault]

The wiring system I used is one that doesn't require breaking or cutting wires, uses an induction loop to detect current change.

@Dark-Fx is this the device you're referring to Tekonsha (119250) T-Connector https://a.co/d/7smDxSh ?

 

[Dark-Fx]

@Dark-Fx any details on this device?

This is the one I've used
https://www.tekonsha.com/product/119250_zero-contact-universal-modulite

I only have left turn and right turn wired up, but that's what the lamp I'm using expects (and I don't want parking lighting)

 

[avigneault]

Great, thank you for that. Looks like this is the ONLY product on the market that works in this fashion... no wonder they can get away with charging $150+ dollars for it!

 

[camaroz1985]

Great, thank you for that. Looks like this is the ONLY product on the market that works in this fashion... no wonder they can get away with charging $150+ dollars for it!

Shop around. I got one for my wife's ID.4, and I think I ended up paying about $80 which was much easier to stomach.

 

[avigneault]

@Dark-Fx did you consider using the 12v supplied to the air compressor in the bed instead of going all the way to the gear tunnel?

 

[Dark-Fx]

@Dark-Fx did you consider using the 12v supplied to the air compressor in the bed instead of going all the way to the gear tunnel?

I didn't want to tap into anything on the truck that long ago and that was before I realized there were multiple air compressors. I'd probably consider doing that now since it would be easier to get to the wiring. Next go around I'm planning on having an aux 12V battery and that'll get wired in directly off one of the extra terminals off the passenger side battery into a dc-dc converter to charge it.

 

[avigneault]

That makes sense, I'm thinking something similar. Considering how many batteries are already in the car, it might make more sense to replace one or both of the AGM 12v batteries with LiFePo and just use those. There's already a DC-DC converter charging them from the main pack (not withstanding recent Rivian bugs). Or just plug a little solar power station like the Ecoflow River 2 into the frunk 12v outlet and use that.

 

[avigneault]

Sit rep: spent about 7 hours straight yesterday working on this project. Some things I can confirm:

1. Even though you can pull a stable 13 volt from the power leads in the tow harness, you can't put any load on it in the absence of signal wire controls. Doing so will cause something on the truck side to freak out, and it goes into some weird pulsing state for a while.
2. There are no suitable 12 volt sources in the bed. Anywhere. The closest thing I could find were the leads servicing the gear guard lock next to the bed compressor, but those are just 20 gauge wires and not designed to handle any sort of real amperage required by the Tekonsha (119250).
3. You must remove all the plastics from inside the bed, starting with the forward-most panel labeled "Rivian." This requires a variety of tools, including a Torx T50, T29 (or T28, can't remember), socket set, and panel puller tool. You'll also need to pull panels from inside the gear tunnel (driver's side), rear seat, B-pillar, and A-pillar in order to run a new 12V line allllllll the way from the frunk. Plan on 30 feet of 12 guage wire to get out there, including connectors, heat shrink, etc.
4. You should avoid tapping off the 12V plug in the gear tunnel, because the Tekonsha requires constant 12V power, otherwise it will go through a re-initialize cycle every time you turn on the vehicle. The 12v in the gear tunnel is switched.
5. Do not. Mount. Anything. Until you have a functioning solution. It is guaranteed to not work. Ask me how I know.

My install still does not work, and I expect to be tearing the whole thing apart again this week, some time. TLDR; if you want to install a functioning third brake light, plan way ahead, own a garage, buy many tools, dedicate an entire day, and expect to fail.

 

[EVTrukHog]

Sit rep: spent about 7 hours straight yesterday working on this project. Some things I can confirm:

1. Even though you can pull a stable 13 volt from the power leads in the tow harness, you can't put any load on it in the absence of signal wire controls. Doing so will cause something on the truck side to freak out, and it goes into some weird pulsing state for a while.
2. There are no suitable 12 volt sources in the bed. Anywhere. The closest thing I could find were the leads servicing the gear guard lock next to the bed compressor, but those are just 20 gauge wires and not designed to handle any sort of real amperage required by the Tekonsha (119250).
3. You must remove all the plastics from inside the bed, starting with the forward-most panel labeled "Rivian." This requires a variety of tools, including a Torx T50, T29 (or T28, can't remember), socket set, and panel puller tool. You'll also need to pull panels from inside the gear tunnel (driver's side), rear seat, B-pillar, and A-pillar in order to run a new 12V line allllllll the way from the frunk. Plan on 30 feet of 12 guage wire to get out there, including connectors, heat shrink, etc.
4. You should avoid tapping off the 12V plug in the gear tunnel, because the Tekonsha requires constant 12V power, otherwise it will go through a re-initialize cycle every time you turn on the vehicle.
5. Do not. Mount. Anything. Until you have a functioning solution. It is guaranteed to not work. Ask me how I know.

My install still does not work, and I expect to be tearing the whole thing apart again this week, some time. TLDR; if you want to install a functioning third brake light, plan way ahead, buy many tools, dedicate an entire day, and expect to fail.

Wow! ...quite a report. Thanks for your intel and props to your perseverance on this. Why in the name of God would you design an "Adventure Vehicle" and not include 12V connections for accessories in the bed?!? ...at what point do you resign to an external battery for your accessories?

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