Decent FJ40 trailer wire connect method

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DenverMike said:
Did everything work out for you? I’m only trying to get wiring so I can plug in an external tow light set up to put on my bike rack so people can clearly see my lights when I’m breaking or turning (and driving at night.). I went to U-Haul today and the guy assured me it would be a simple install an hour and a half later he had somehow managed to melt my brake light relay switch and only get the running lights and turn signals working.
here’s a pic of my funny little connector that Uhaul bypassed entirely - and a pic of my melted switch.

View attachment 2725710

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Click to expand...

Hey man, sorry I wish I could be of more help. That was a while ago and I have since sold that truck, regretfully. You may have to get a multimeter and start testing which wire is getting power when you are doing which function from the front of the truck, and narrow it down from there.

I am far from an electrical guru, maybe someone can chime in and help you out.

Good luck with that, I know it’s a pain!

Joel
 
I'm in the process of trying to setup trailer wiring on the 40. It's a February 1976

I have the signal box. I didn't go with a powered one as I'll really only be pulling my little camping trailer and all of the lighting is LED. I don't thing the draw justifies the powered unit. It should be almost nothing.

Forward of the rear axle there is this connector that goes aft to the lighting assemblies.

This seems like the easiest place without hacking into the harness.

20240708_105146.webp



This is the layout of that plug.
(Tab is up)

20240708_105109.webp


And the female plug on the aft harness.

20240708_105156.webp




What I would like to do is find these two connectors to make my own "no cut" option. Somebody on here is selling some of these components. @Trollhole ?

Just looking for the least invasive option.

I'm going to be putting a 7 pin RV style plug on the vehicle up behind the bumper. I'm going to run accesory power to the trailer for things like a USB charger and some LED lighting under the hood. The trailer has reverse lights too.
 
sogncab said:
I'm in the process of trying to setup trailer wiring on the 40. It's a February 1976

I have the signal box. I didn't go with a powered one as I'll really only be pulling my little camping trailer and all of the lighting is LED. I don't thing the draw justifies the powered unit. It should be almost nothing.

Forward of the rear axle there is this connector that goes aft to the lighting assemblies.

This seems like the easiest place without hacking into the harness.

View attachment 3672738


This is the layout of that plug.
(Tab is up)

View attachment 3672739

And the female plug on the aft harness.

View attachment 3672740



What I would like to do is find these two connectors to make my own "no cut" option. Somebody on here is selling some of these components. @Trollhole ?

Just looking for the least invasive option.

I'm going to be putting a 7 pin RV style plug on the vehicle up behind the bumper. I'm going to run accesory power to the trailer for things like a USB charger and some LED lighting under the hood. The trailer has reverse lights too.
Click to expand...
It appears that @Coolerman has what you need:


Click on "74-83 Terminals/Connectors" and scroll down to the six pin connectors.

If you're not experienced, order some spare brass terminals; you may have to practice on a few to ensure you're crimping effectively.
 
sogncab said:
I'm in the process of trying to setup trailer wiring on the 40. It's a February 1976

I have the signal box. I didn't go with a powered one as I'll really only be pulling my little camping trailer and all of the lighting is LED. I don't thing the draw justifies the powered unit. It should be almost nothing.

Forward of the rear axle there is this connector that goes aft to the lighting assemblies.

This seems like the easiest place without hacking into the harness.

View attachment 3672738


This is the layout of that plug.
(Tab is up)

View attachment 3672739

And the female plug on the aft harness.

View attachment 3672740



What I would like to do is find these two connectors to make my own "no cut" option. Somebody on here is selling some of these components. @Trollhole ?

Just looking for the least invasive option.

I'm going to be putting a 7 pin RV style plug on the vehicle up behind the bumper. I'm going to run accesory power to the trailer for things like a USB charger and some LED lighting under the hood. The trailer has reverse lights too.
Click to expand...

Keep in mind your 40 runs a separate wire for the brake and the trailer lights need to mimick the 40's lights or you'll need a converter.
 
Since you plan on running a separate 12 volt source I would use a converter with a separate power feed. You have to run a power wire from the front anyway. Even with LEDs you run the risk of a wire shorting to ground. If you make a small double connector would not use the ground but rather make a new. Would assume your power plugs need a ground besides the trailer hitch. Would have the trailer have it's own dedicated ground the ground for lights on the back of the cruiser. Wiring is forty eight years old.

My 76 has that same plug and also has plug with three wires Red, yellow and green. Each has two wires like connector is acting like splice. Also a two pin connector with both plugs. Black and white wires. Then to green wires leading to a bullet connector taped to the harness. Green wire have a trace color but until I plan to identify each wire not going to disturb it.
PXL_20240708_201423339.webp

PXL_20240708_201447599.webp
 
Living in the Past said:
Since you plan on running a separate 12 volt source I would use a converter with a separate power feed. You have to run a power wire from the front anyway.
Click to expand...

I'm going to be running power off a switched relay.
I need to look into it more, but I think I'm going to put a small battery in the trailer as well so it doesn't have to be connected to charge a phone or power up the lights.

I have one of those green plugs at the rear cross member. It's been hacked up little bit. That's why I was thinking that forward plug would be a decent choice
 
sogncab said:
I'm going to be running power off a switched relay.
I need to look into it more, but I think I'm going to put a small battery in the trailer as well so it doesn't have to be connected to charge a phone or power up the lights.

I have one of those green plugs at the rear cross member. It's been hacked up little bit. That's why I was thinking that forward plug would be a decent choice
Click to expand...
Hey Karl, what did you end up doing here?

The Reverend thanks you—-
 
RevISK said:
Hey Karl, what did you end up doing here?

The Reverend thanks you—-
Click to expand...


I bought a new harness from trollhole with a 4 pin connector out the back and the decoder box for under the hood.

Still planning on running an auxiliary power back to a 7 pin trailer connector. I need to do that so I can use the reverse lights in the trailer as well.

Haven't made to tackling the trailer side of things yet. I keep trying to hone in on what I want, and how I want to do it. The goal posts keep moving on me though. Analysis paralysis....

I did learn last year in Colorado i want brakes on the trailer. I haven't felt i needed it on pavement, but i got pushed around a bit on dirt in some tight sections going downhill. Which also tells me, might not be a bad thing on pavement.
Thought it might be beneficial to have brakes and the ability to just lock them. I ordered a unit from Redarc. I still need to order brake parts for the trailer.


I think the way I'm going to handle battery needs in the trailer with is one of those "battery generator" units that also does 120v.
One i was looking at one that had a 12V in, so you could charge it from the vehicle. Also had 12V out. I'd run the lighting and outlets in the trailer with that. They had matching solar panels as an option as well.

I also had some tabs welded underneath for lights. I've got this idea I want to illuminate the ground under the trailer when parked and also be able to kick on the running lights and reverse lights with a switch as well.






@mytlcexperience on Instagram: "More random #solidaxlesummit8 pictures Barely a week and a half since we left and I miss it already." - https://www.instagram.com/p/C-_z-ecND9C/?igsh=dGg3cWQ2bzl2NWV4
 
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