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Trailer lights not working

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No issues on my trailer with all LED lighting but that was in a 7-pin connection. Do you have another 7-4 adapter you could try?
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I tried three different adapters. As soon as I added more resistance the lights worked. With the park lights working which have 4 lights but the rest does not work also tells something.
 
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Lots of people are using trailers with LED lights without a problem. Seems like a leap to conclude that "Rivian has a build problem with trailer lights and since it is illegal to sell incandescent lights it has a problem with all new trailers".

So what could be wrong? One issue that people have had is that the 7 pin outlet on the Rivian is pretty tight, and unless you push the plug in really hard the pins might not all make a connection.

Also if you've built your own 7-to-4 adapter, I would check the pinouts carefully.
 
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Well there is only one trailer I care about lights working and it is the one I have to tow right. No other trailer matters at that point. So if the lights work on the truck I get the trailer from it is not the trailer, right? The park lights work so there are connection between the adapter and the 7 pin contacts. Also the adapter was deep enough for the cover to lock it in. However when I added resistance to the brake lights they worked. That leaves only one conclusion. Rivian does not sense the lights and thus not provide power to the brake lights. I tried three different adapters with the same outcome. They were store bought.
 

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It depends on the resistance of the lights. Led lights have low resistance if the manufacturer added a resistor inline it will negate the problem but not all do.
 
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Mine works fine with LED lights. It's difficult to check that they are working by yourself though, because it turns them off quickly when you exit. Recommend hitting the hazards instead of the turn signal.

I second the suggestion to double check that you have the adapter inserted completely, if the latch doesn't come down then it for sure needs to get pushed in further. It can definitely feel like it's all the way in earlier than that.
 
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It was plugged in correctly I do trailers all the time. There were two of us me and the driver of the Silverado. The same adapter worked on the Silverado just fine. It is a build issue on the Rivian.
 
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Given the successful experience of several others, and that this didn't come up over the last 2+ years of production vehicles being used in the real world, gonna go ahead and say the hypothesis that was stated as fact by OP is wrong...
 
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LOL
 

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Have used many trailers varying from new to old using 7 pin to 4 pin adapters. Have never had an issue. Have used both LED and non-LED lights.

Are you sure you're plugging it in all the way? Does the Rivian recognize that a trailer is connected? (Should pop in to trailer mode).
 
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Have used many trailers varying from new to old using 7 pin to 4 pin adapters. Have never had an issue. Have used both LED and non-LED lights.

Are you sure you're plugging it in all the way? Does the Rivian recognize that a trailer is connected? (Should pop in to trailer mode).
 
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It's plugged in all the way. I have park lights but nothing else. It works when I add resistance to the light circuit. The lights work on every other vehicle I tested it on including my wifes Model Y. It is a Rivian build problem. I plan using the trailer frequently and plan on adding resistance inside the adapter for the lights that does not work. It is cheaper than to modify the trailer and replace the lights.
 
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No problem with LED 4-pin-connected trailer lights here. Don't just assume that because you are having a problem that it is a design problem with all vehicles. It isn't that you have LED trailer lights, it's something else. Sure, there might be an individual problem with your vehicle, but it isn't a design defect.

And incandescent lights aren't illegal to sell, it's "high power household incandescent bulbs" that are currently banned. Smaller/special-purpose lights, such as vehicle bulbs, are still 100% legal and readily available at stores both brick-and-mortar and online.

Edit to note: I actually have the opposite problem. When I plug in my small cargo trailer with LED lights, the slight 12V leakage current means they're on dimly even when my truck lights are off and the vehicle is locked. It's not visible during the day, but at night if the truck+trailer are parked where it's dark, you can see a small amount of red light coming from the trailer lights. When the vehicle is on, the trailer lights are at full proper brightness.
 
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It is the same with mine there is a leak current to the lights. I think that is what is used to sense if a trailer is present. The light circuit is not turned on because I think it sense resistance and Led lights have a low resistance. I simply added my test lamp between the Led light and the truck. That increased the resistance and the circuit turned on. Led lights have an or should have a inline resistor but not all lights a re equal. I think turning off or not turning on a circuit for lights is not safe. When a trailer is sensed all the lights should be turned on. If there is a short (low resistance) it should simply blow the fuse. It is a Rivian build problem and a safety issue. I plan on adding resistance to the lights inside the 7 to 4 pin converter to resolve the issue and still be able to use the trailer on other vehicles
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