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Towing Camper with Model S 85D?

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I don't see how that makes a difference - Maybe you pulled the marker and turn signals from different source wires than I did, but using the relay pack versus directly wiring it shouldn't matter, that is only a means of separating the two lighting systems from possibly overloading each other.

Where did you pull the lighting signals from? I got mine from the harness on the back of the lights on each side, I'd have to pull the covers to see what the colors are. I was following the video tutorial that was posted elsewhere here on TMC.



I don't always pull the exact same trailer - witness the three different ones I pictured above, and Uhaul frequently has old incandescent lighting rather than LED b/c they use their equipment to destruction (which can take a LOOOOOOOONG time for their trailers). So the relay pack was a personal requirement to protect the car's electronics from any trailer funny business that might happen.
Yeah it's possible I used different wires. I'd have to pop off the panels to see which ones I used. I know one of them was way up by the headrest for the rear right seat that one was a PITA to get to because there wasn't much slack in the line. The others I got from the right side and 1 from the left.

And yeah in your case it makes sense to have it wired up to not splice but I still dono if it would be a problem it's just something I hypothesized when I was doing it since LED draw like 0.2A vs an incandescent trailer light drawing like 2A so I figured since the car wasn't designed to have that much current draw it might pop a fuse or start throwing lots of errors but I dono if it actually would.
 
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Dmwahl great feedback on your experience. So instead on running a power lead (fused ) from battery directly, you where able to successfully tap the positive from the trunk ?
That's right. It's on the passenger side of the car, above the rear wheel well in my car. I had to figure out which the 12V supply wire was, but after that it was easy. There's a big bundle of wires with a few obviously larger gauge than the others. In my case only one had 12V on it when the gate was up so it was pretty obvious. I also confirmed it with a wiring diagram I found online somewhere. There was a ground screw nearby as well for the ground wire. Both my trailers have LED lights, but I doubt even if they were incandescent it would cause an issue.
 
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geordi, thanks for the insight. So regardless of how I set up the trailer wiring , for my turn signals to be working , I am going to have to make sure the park lamp/headlamp are active , so I assume auto will not turn on headlamps during the day ?
There is a fix for the tail light and turn signals to work. This has been covered a few times on TMC. You can combine the left and right tail lights using a relay to activate the trailer tail lights only when both the Tesla right and left tail lights are on.

What happens is that during the day with no lights, the Tesla activates the right tail light when the right turn signal is on and activates the left tail light when the left turn signal is on. The tail lights are also activated during braking.

When the lights are on for nighttime driving, the Tesla activates the right and left tail lights all the time.

Therefore if you tap into only the left or the right tail wire for your trailer, during the day the trailer tail lights will flash when you turn right or left (depending on which one you tapped). This behaviour is not good because when you turn, the tail lights on all sides of the trailer flash and can confuse other drivers. Turning on the headlights fixes this behaviour because the tail lights are activated all the time.

The relay solution of combining both left and right tail signals for the trailer wiring changes the behaviour to be more normal. I have done this and now the trailer tail lights do not flash when turning during the day. However the tail lights still light up when braking which is not really a problem. When the lights are on, the tail lights are on so no problem at night either.

You can see how I wired up my trailer 4 pin with an inexpensive 4 relay board here. It is all powered with the power lift gate 12V+ on the right side of the trunk. No need for the expensive Tekonsha relay kit that doesn't even solve this problem.
 
There is a fix for the tail light and turn signals to work. This has been covered a few times on TMC. You can combine the left and right tail lights using a relay to activate the trailer tail lights only when both the Tesla right and left tail lights are on.

What happens is that during the day with no lights, the Tesla activates the right tail light when the right turn signal is on and activates the left tail light when the left turn signal is on. The tail lights are also activated during braking.

When the lights are on for nighttime driving, the Tesla activates the right and left tail lights all the time.

Therefore if you tap into only the left or the right tail wire for your trailer, during the day the trailer tail lights will flash when you turn right or left (depending on which one you tapped). This behaviour is not good because when you turn, the tail lights on all sides of the trailer flash and can confuse other drivers. Turning on the headlights fixes this behaviour because the tail lights are activated all the time.

The relay solution of combining both left and right tail signals for the trailer wiring changes the behaviour to be more normal. I have done this and now the trailer tail lights do not flash when turning during the day. However the tail lights still light up when braking which is not really a problem. When the lights are on, the tail lights are on so no problem at night either.

You can see how I wired up my trailer 4 pin with an inexpensive 4 relay board here. It is all powered with the power lift gate 12V+ on the right side of the trunk. No need for the expensive Tekonsha relay kit that doesn't even solve this problem.
Jjvan excuse my ignorance , I guess my 15 volts lithium battery has got me all overly concerned . Thank you for the input , and explanation. Tomorrow I am going to Uhaul and try to explain that they may not know all the facts for the wiring installation as it’s their 1st 2022 Model S 🤞🏼
 
Jjvan excuse my ignorance , I guess my 15 volts lithium battery has got me all overly concerned . Thank you for the input , and explanation. Tomorrow I am going to Uhaul and try to explain that they may not know all the facts for the wiring installation as it’s their 1st 2022 Model S 🤞🏼
Jjvan I read some of your previous post on trailer relay connections. Good info.
I wanted to know where you installed your 7 pin trailer connectors on your model S ? It looks very limited For space . Did you use a magnet 🧲 like Airborne did ?
 
Jjvan I read some of your previous post on trailer relay connections. Good info.
I wanted to know where you installed your 7 pin trailer connectors on your model S ? It looks very limited For space . Did you use a magnet 🧲 like Airborne did ?
I kept the trailer plug in the trunk and pull it out when needed for the trailer. I didn't want the trailer plug to be exposed to the elements all the time and I didn't want to drill any holes in the frame. I use the 4 pin connector and the 4 wires are small enough to fit nicely through the trunk door seal. I have not noticed any issue with that so far.
 
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I kept the trailer plug in the trunk and pull it out when needed for the trailer. I didn't want the trailer plug to be exposed to the elements all the time and I didn't want to drill any holes in the frame. I use the 4 pin connector and the 4 wires are small enough to fit nicely through the trunk door seal. I have not noticed any issue with that so far.
Yeah that would be the way I'd done it if i didn't tow very often and i had it like that for a while, and if all the wires are flat its easy enough. But I'm going to live on the road with my trailer so it will basically always be towing which is why i wanted a different way because it cant be good for the wires or the seals to get crushed constantly
 
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Yeah that would be the way I'd done it if i didn't tow very often and i had it like that for a while, and if all the wires are flat its easy enough. But I'm going to live on the road with my trailer so it will basically always be towing which is why i wanted a different way because it cant be good for the wires or the seals to get crushed constantly
I can see your reasoning for continuous trailer use and I like your magnet solution. I also like your D-ring shackle solution for making chaining up the trailer to the hitch easier. I will look into doing that as well.
 
Here is the links I used, I put a 1/2" washer on each side to make it more solid.
I'll take a pic of how I did up my wiring in the morning as it's dark and stupid cold/windy now. A hint though… magnet 😎

Also FYSA I didn't install a brake controller because my trailer is reasonably light and a lot of states don't need one unless it's over 2500lbs. But I did install a 7 pin because I used the 12v and ground coming from the trailer battery to the trunk to power my 12v fridge/freezer combo. That way I'm using the trailer solar power to keep the fridge running and not wasting car battery power on it.

View attachment 899054
I couldn’t find a quick link big enough locally , that could handle my tow rating , but I found this from another post ENIXWILL 2pc 1/2 inch Tow Hitch Safety Chain Connector Link Hammerlock Grade 80 Coupling Link Red https://a.co/d/dSTQ0Dz
Hopefully they can make the safety chain easier to attach 🤞🏼
 

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I couldn’t find a quick link big enough locally , that could handle my tow rating , but I found this from another post ENIXWILL 2pc 1/2 inch Tow Hitch Safety Chain Connector Link Hammerlock Grade 80 Coupling Link Red https://a.co/d/dSTQ0Dz
Hopefully they can make the safety chain easier to attach 🤞🏼
yeah but to install those you'd have to get in there with the bumper off or have very small hands to be able to get the hammer to install those. do you not have home depot or amazon up there in Americas hat? lol

 
yeah but to install those you'd have to get in there with the bumper off or have very small hands to be able to get the hammer to install those. do you not have home depot or amazon up there in Americas hat? lol

Ohh I didn’t think about only the way to attach was bumper off. Well I’m from Canada and home depot locally had 1800 lbs strength 3/8 , yeah may have to go Amazon for the 1st picture shackle you got there . Thanks Airborne
 

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Ohh I didn’t think about only the way to attach was bumper off. Well I’m from Canada and home depot locally had 1800 lbs strength 3/8 , yeah may have to go Amazon for the 1st picture shackle you got there . Thanks Airborne
yeah you need 1/2" for the quick link to be up to the weight but for the D-ring shackle you can get with 3/8" but ya gotta pay attention to it because some are 3/8" and handle 2200lbs and some 3/8" only handle 1900lbs. but yeah quick links ya need 1/2"
 
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Do you really need something that big for the weight? Unless the rest of your safety chain is just as big it will just break one of those links if it's going to go.
Well the chains do look 👀beefy , and the trailer is 3500 lbs, but honestly when *sugar* hits the fan, I’m thinking the chain would be pulled straight and the hitch safety chain attachment being so high up, the rear bumper is gonna get cut in half anyways 🤷🏼
 

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Do you really need something that big for the weight? Unless the rest of your safety chain is just as big it will just break one of those links if it's going to go.

TL;DR yes, Everything is rated to a certain weight.

Trailers come from the factory with chains and hooks that are rated at or above the GVW of the trailer by law. As a consumer you can mod that to suit your needs (provided its still within law, eg. not putting 2000lb rated stuff on a 4000lb trailer). Like my trailer came with 5/8" S hooks but it doesn't need anything bigger than 3/8" but I'm not gonna change them out unless they break.

so if the trailer is 2000lbs then EACH chain needs to support a working weight of at least 2000lbs, and if you add links like in my case a quick link and a d-ring each of those have to be able to hold at least 2000lbs as well. A lot of people think that it is supposed to be the trailer weight split between the 2 chains but this is wrong and unsafe. Also chains should be hooked up crossed in an effort to "catch" the hitch if it falls off and prevent it from digging into the road.

Another spec that needs to be looked at is the breaking force for a chain like all my stuff the weakest one has a breaking force of 8500lbs which is important because if the trailer falls off the hitch there will be a lot more force applied to it than just the 2000lb trailer so usually you want to look for at least 2 times the weight of the trailer as the breaking force but 3 times or higher is best.
 
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I completely agree with using properly sized safety chains, I didn't look at the rating on the links pictured above and was surprised at how low a weight rating they have for a 3/8" link. The chains and links that came on my boat trailer (2995 GTW) are 1/4", and then looking at an etrailer listing for a 5000lb trailer chain they have 1/4" chain and links (https://www.etrailer.com/Trailer-Safety-Chains/Titan-Chain/TCTSCG30-772-07x2.html). Granted the etrailer stuff is probably better steel than the everbilt.

If you have links to the regulations or laws or whatever state's the rules I'd be curious to read it. For me I used a 3/8" link between the receiver and chains, but that was mostly because the smaller ones didn't open enough to easily get them onto the receiver.
 
I completely agree with using properly sized safety chains, I didn't look at the rating on the links pictured above and was surprised at how low a weight rating they have for a 3/8" link. The chains and links that came on my boat trailer (2995 GTW) are 1/4", and then looking at an etrailer listing for a 5000lb trailer chain they have 1/4" chain and links (https://www.etrailer.com/Trailer-Safety-Chains/Titan-Chain/TCTSCG30-772-07x2.html). Granted the etrailer stuff is probably better steel than the everbilt.

If you have links to the regulations or laws or whatever state's the rules I'd be curious to read it. For me I used a 3/8" link between the receiver and chains, but that was mostly because the smaller ones didn't open enough to easily get them onto the receiver.
I had already ordered last night from Amazon
FCF1C5BF-EB95-4B39-B65B-CFF9301B3D55.jpeg

Ucreative 2Pcs Synthetic Soft Shackle 1/2 Inch x 22 Inch (55,000lbs Max Breaking Strength) with Extra Sleeves (Gray) https://a.co/d/9on1WtJ
, after going to Home Depot and only found 3/8 quick links . So Amazon showed up today after my hitch install . Going to give them a try , God forbid that I ever have to actually use them in a situation.
U-Haul took so long with hitch and wiring , I had to step into help them out (gave me $110 off my invoice ) quoted 3 hrs labour @$80 usd /hrs . I was there from 9am till 6 pm . The young fellow said it was his 1st MS . U haul Head office only had Information up to 2020 MS . He got confused how to latch onto a Tesla lithium 16v battery
79A3BCDB-7634-48E7-A56C-7B5541FC8396.jpeg


There was a red positive post that was in a shape of a square blade covered with a red cap and + sign on it lol . Told him to drill a small hole and nut n bolt that eye hook positive wire coming from Tekonsha ZCI in the back
DDEA85EB-FF24-43AA-B23C-07972CE1AA84.jpeg

I would have done this myself at home but don’t have the ramp and lifting equipment, to remove the bumper . I helped him test the lights and signals with headlights on and off , he said it all works . I will get my own tester to reconfirm . So the only thing I did different was I got the battery direct wired , according to the Tekonsha manual , says not to tap into an ignition positive. ( not sure if trunk wire + was considered a ignition positive ) Thanks for all the feed back on this install , couldn’t have got my 150 discount with out the TMC family knowledge 🙌
 

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I had already ordered last night from Amazon View attachment 900568
Ucreative 2Pcs Synthetic Soft Shackle 1/2 Inch x 22 Inch (55,000lbs Max Breaking Strength) with Extra Sleeves (Gray) https://a.co/d/9on1WtJ
, after going to Home Depot and only found 3/8 quick links . So Amazon showed up today after my hitch install . Going to give them a try , God forbid that I ever have to actually use them in a situation.
U-Haul took so long with hitch and wiring , I had to step into help them out (gave me $110 off my invoice ) quoted 3 hrs labour @$80 usd /hrs . I was there from 9am till 6 pm . The young fellow said it was his 1st MS . U haul Head office only had Information up to 2020 MS . He got confused how to latch onto a Tesla lithium 16v battery View attachment 900567

There was a red positive post that was in a shape of a square blade covered with a red cap and + sign on it lol . Told him to drill a small hole and nut n bolt that eye hook positive wire coming from Tekonsha ZCI in the back View attachment 900570
I would have done this myself at home but don’t have the ramp and lifting equipment, to remove the bumper . I helped him test the lights and signals with headlights on and off , he said it all works . I will get my own tester to reconfirm . So the only thing I did different was I got the battery direct wired , according to the Tekonsha manual , says not to tap into an ignition positive. ( not sure if trunk wire + was considered a ignition positive ) Thanks for all the feed back on this install , couldn’t have got my 150 discount with out the TMC family knowledge 🙌
Sorry I don’t know how that monkey emoji got there … fat fingers