Got hitch but I can’t find light plug

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Bombastinator2

Well-known member
Joined
Jan 3, 2024
Messages
399
So I had a hitch installed but I can’t find the connection for the lights. Is it in some unusual place on leaf’s or did the installer just not do it?! Is it unusual in electric cars or something?
 
I wouldn’t be surprised if the installer didn’t install light wiring. The Leaf is not really made to tow, the hitches are meant for bike racks etc.
 
The Leaf (at least our 2020 SV+) is rated for towing 1,500 pounds. I installed a hitch from eTrailer.com (I have one on my 2018 Prius Prime as well, same towing capacity. eTrailer has vehicle specific hitches). The wiring harness was a separate item. If you can't find the plug somewhere inside the back hatch the installer probably failed at the job or didn't understand you wanted lights. There should be a (probably red) wire with a fuse up on the 12V battery if they did install the harness. I suppose one could mount a permanent receptacle under the bumper but for occasional use bringing the wire out through the hatch is perfectly adequate.
 
So it looks like I’m splicing. I need to do things quick. Any instructions on which wire I should splice to which and where said wire would be?
The kit has some split adapters to tap the brake lights and blinkers without cutting any wires, but you can do the same thing manually with typical auto-splice connectors. The kit also comes with a power booster to make the trailer lights brighter, but I didn't use it on mine because I found just buying LED light-bulbs for the trailer and replacing the incandescent bulbs worked just as well without putting a big power load on the rear lights themselves. You basically have to take the rear trunk floor apart and the side plastic panels to get to those wires on each side for the tail-lights.

I don't have the old wiring diagram that came with my kit, but you only need a common ground to the frame, one wire from the left and right blinkers and a brake light wire to splice into. Basically, you'll need a plug and cable with the colors labeled as to which goes to which. 🤨

I ran my wire harness through the already existing but plugged with a rubber stopper middle hole in the rear trunk, so it comes out in the rear air diffuser, then run along to the hitch itself.
 
The kit has some split adapters to tap the brake lights and blinkers without cutting any wires, but you can do the same thing manually with typical auto-splice connectors. The kit also comes with a power booster to make the trailer lights brighter, but I didn't use it on mine because I found just buying LED light-bulbs for the trailer and replacing the incandescent bulbs worked just as well without putting a big power load on the rear lights themselves. You basically have to take the rear trunk floor apart and the side plastic panels to get to those wires on each side for the tail-lights.

I don't have the old wiring diagram that came with my kit, but you only need a common ground to the frame, one wire from the left and right blinkers and a brake light wire to splice into. Basically, you'll need a plug and cable with the colors labeled as to which goes to which. 🤨

I ran my wire harness through the already existing but plugged with a rubber stopper middle hole in the rear trunk, so it comes out in the rear air diffuser, then run along to the hitch itself.
The thing i am looking for is where the wires that is need to connect to are and how to get to them. I take it there is no factory pre wiring and i need to use a 5-4 adaptor. So left & right blinkers, brake, headlights, and ground (which can be anywhere on the frame). The ground is likely easy, but finding the other four is likely a bit complicated
 
The kit has some split adapters to tap the brake lights and blinkers without cutting any wires, but you can do the same thing manually with typical auto-splice connectors. The kit also comes with a power booster to make the trailer lights brighter, but I didn't use it on mine because I found just buying LED light-bulbs for the trailer and replacing the incandescent bulbs worked just as well without putting a big power load on the rear lights themselves. You basically have to take the rear trunk floor apart and the side plastic panels to get to those wires on each side for the tail-lights.

I don't have the old wiring diagram that came with my kit, but you only need a common ground to the frame, one wire from the left and right blinkers and a brake light wire to splice into. Basically, you'll need a plug and cable with the colors labeled as to which goes to which. 🤨

I ran my wire harness through the already existing but plugged with a rubber stopper middle hole in the rear trunk, so it comes out in the rear air diffuser, then run along to the hitch itself.
The thing I am looking for is wire location and how to get to them. Normally there is a video for a given model, but none for the leaf (of any year) that I can find,or even anything written anywhere (unless someone knows where such might be) so this is effectively exploratory surgery. It seems my best hope is to find the various lights, and look for the wires trailing from them. The leaf like most newer cars needs a 5-4 adaptor, so I need to find the left & right blinkers, brake, headlight (night) and ground (which is anywhere on the frame and therefore pretty easy). I’ll just have to basically take the entire back end of the vehicle apart looking for them. Highly frustrating.
 
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I was able to find a thing explaining how to take apart the tail lights. Now I just have to find a way to get to both sides. Some trim is definitely coming off I think. That hole thing sounds like it might be useful if I was installing a port.
 
The thing i am looking for is where the wires that is need to connect to are and how to get to them. I take it there is no factory pre wiring and i need to use a 5-4 adaptor. So left & right blinkers, brake, headlights, and ground (which can be anywhere on the frame). The ground is likely easy, but finding the other four is likely a bit complicated
Unfortunately, no pre-wiring anywhere. Basically, after taking apart the rear bottom interior, you'll have to manually figure out which wire goes to which blinker light, brake lights, etc. I do remember that most of those wires are on the "left" side when facing the rear and a single wire was needed to reach the right blinkers, so I think most of your splice will take place on the left side.

I think once you take everything apart, the wires are easy to follow. All the "kit" does is give you a splitter on the "plug" for the lights to avoid splicing into the wires directly, but even if I didn't have those splitters, I remember it being easy to splice into the wires if needed since it's kind of a "one-time" wiring that would be pushed back under the panels and tucked away when done.
 
WHAT???? Splice wires?? HELL NO!!! The wire harness I got from eTrailer.com didn't require any wire splicing. No guessing which wire is brake, turn signal, etc. It came with connectors that go into the OEM connectors for the rear lights. The ugly part was running the power wire up the driver's side under the door sill covers and through a grommet in the firewall. Instructions for the Prius Prime had me run the wire under the car body, above the plastic undercarriage panels.
 
‘Im a cheap bastard though. Just gonna use those little splicing blocks. That way aside from buying splicing blocks i can use stuff i already got. How to get the wire to the battery is good info though. sill covers huh. I’m not going to enjoy that. The one wire to the right side is probably the blinker. There’s a handy little door in the left rear i can stuff the cord in. I could do the lighter and electric tape thing but it seems extreme. Splicing blocks are cheap.
 
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Being that the lights are controlled by the BCM, you may find that screws up there operation. Trailer light controllers for 3 to 2 light systems made for newer cars with LED lights have their own power wire so to not cause a problem. You also may overload the cars wiring.
Your trailer will need separate turn and brake lights also, as that is the system the Leaf uses, unless you use a converter.
In the industry, we call those little "splicing blocks" "corrosion clips" for a reason!
 
I recently installed a hitch and lighting. I used the cheap-ish powered adapter. (probably Hopkins)

After removing the taillights, I spliced into the harness and I mounted the adapter to the sheet metal below the driver's side taillight.

IIRC, I ran the wire to the right taillight by tucking it behind the bumper cover, but I don't recall if I did that by removing the plastic underbody panel.

I ran the power wire up to the 12V battery along the side of the traction battery.
 
‘Im a cheap bastard though. Just gonna use those little splicing blocks. That way aside from buying splicing blocks i can use stuff i already got. How to get the wire to the battery is good info though. sill covers huh. I’m not going to enjoy that. The one wire to the right side is probably the blinker. There’s a handy little door in the left rear i can stuff the cord in. I could do the lighter and electric tape thing but it seems extreme. Splicing blocks are cheap.
You can't be too cheap a bastard if you paid someone to put the hitch on ;) Out of curiosity, what did the hitch and installation cost?

However I just looked at the price of the

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector​

Item # C56227
$77, not cheap. And I'm sure more than I paid 3 years ago. But it sure was easy to install, unplug the connector to the light, put the Curt connector inline, done.
 
You can't be too cheap a bastard if you paid someone to put the hitch on ;) Out of curiosity, what did the hitch and installation cost?

However I just looked at the price of the

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector​

Item # C56227
$77, not cheap. And I'm sure more than I paid 3 years ago. But it sure was easy to install, unplug the connector to the light, put the Curt connector inline, done.
TLDNR: what it cost
The hitch system hardware was a couple hundred by itself and they wanted a bit over $400, which implied to me that they would be spending another $30 on lighting wire and doing that up too. 1/2 parts and 1/2 labor is the usual breakdown. They wanted another $300 to do the wiring when I called them with “where is my 4 pin connector?!” So I ordered a generic 5-4 off Amazon and am gonna do it myself.

TLDNR: why I hired it out
The hitch attaches to the underbody, and while I could do it with jack stands, I don't have a lift or a shop, and didn’t much fancy crawling under the car. I’m too old for that stuff. My body isn’t what it was. I’m not sure I could even lift the hitch hardware anymore. About 15 years ago I had a hundred pound bag of road salt over my shoulder for my tenants (I was a landlord) and I plopped it down in the fall, and in the spring I tried to pick it up. Couldn’t even shift it. It’s like it was nailed to the pavement. Andropause is real.
 
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Being that the lights are controlled by the BCM, you may find that screws up there operation. Trailer light controllers for 3 to 2 light systems made for newer cars with LED lights have their own power wire so to not cause a problem. You also may overload the cars wiring.
Your trailer will need separate turn and brake lights also, as that is the system the Leaf uses, unless you use a converter.
In the industry, we call those little "splicing blocks" "corrosion clips" for a reason!
Eeeeww. Would rubber tape solve that issue? Or is it an electro negativity thing I can’t avoid?

TLDNR: rubber tape
I’m talking about old style electric tape made of rubber, not the modern plastic crap that doesn’t reliably waterproof stuff. It used to be code on small engine harnesses. It’s like 5 times as thick and it sort of welds to itself. You wind up eventually with what amounts to a wad of vulcanized rubber covering whatever. One of those wonder materials of world war2 like duct tape. They also did a liquid goo you brushed on. I’ve got the tape though. I use it to protect some cords that don’t have strain arrestors. It sort of gets stick eventually so I wrap it in toilet paper then remove it. One layer stays which is enough to remove the stickiness. Spit works too but only till it evaporates.1716707906272.jpeg
 
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I wouldn’t be surprised if the installer didn’t install light wiring. The Leaf is not really made to tow, the hitches are meant for bike racks etc.
Found it towed fine. Great even. I can use the trailer as a flatbed during the day as long as my car’s tail lights are visible. It’s when I put the sides on or want to use it at night that I’m screwed.

TLDNR: making fun of pickup trucks
Trailers beat the snot out of pickups most of the time.
Pickups have a use but 99% of the people that buy them don’t have a need and are idiots. See a suspiciously shiney custom pickup with a fiberglass bed cover that’s not towing something gigantic? Guaranteed Idiot. Fiberglass bed covers prevent 90% of what a pickup is even good for. Dude has a two seat sedan that gets horrible mileage and has too much trunk. Probably parks backwards too. They actually did research on that one. Unless you’re a professional driver that backs up for a living it’s slower.
 
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💯💯
I sold my truck and got a sedan with a roof rack and a 5x9 flat trailer.

The Leaf tows like a beast.
 

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