Flat towing the 40, and tapping into the existing wiring for lights. Best way? (1 Viewer)

[BrianSanDiego]

Hey all,
I flat tow my '73 FJ40 and use magnetic trailer lights, but would like a cleaner setup.

I know about running the trailer wires from the towing vehicle (truck in front), and tapping into the wires at the FJ40s taillights (towed vehicle). And adding diodes to make it all work. But, I hear you loose turn signals when hitting the brakes.

Is there a location in the 40's wiring, maybe up under the dash, that I could tap in with the trailer power from the towing vehicle, to make my lights on the 40 work correctly?

I know Coolerman does a lot of work with wiring harness, I wonder he or anyone else has figured this out.

...worth a shot!

Thanks, B.

 

[pjohnson]

Yup, @Coolerman has your solution. I think the old thread was recently resurrected as well.

 

[pjohnson]

Found it.

Flat Tow Harness 3L2H for FJ40

The 3L2H Harness (Named after My son dad and me our initials) Here is what I would say. Feel free to modify it. L2H stands for Dr Louis Houston Hagler and Louis Henry Hagler me. And Louis Harve Hagler my dad god rest his soul. The 3L2H Harness: Coolerman has a fantastic new product for Flat...

forum.ih8mud.com

 

[kevos37]

When I had a tow vehicle a while back instead of using the magnetic or towed vehicle lights I made a bar with lights that hooked into the trailer hitch receiver. I ran a trailer multi wire though the length of the vehicle. This enabled me to hook up to the tow vehicle quickly . Also you put a disconnect for the tow bar light. Of course this will only work if you have a hitch receiver on your rig.

Kevo

 

[BrianSanDiego]

Yup, @Coolerman has your solution. I think the old thread was recently resurrected as well.

Thank you. I actually just saw that thread and that's what peaked my interest. Following up on Coolermans website I saw his stuff was for a 1974 or later, which leaves me out. Thought I'd start another thread instead of hijacking that one.
Thanks man.

 

[BrianSanDiego]

When I had a tow vehicle a while back instead of using the magnetic or towed vehicle lights I made a bar with lights that hooked into the trailer hitch receiver. I ran a trailer multi wire though the length of the vehicle. This enabled me to hook up to the tow vehicle quickly . Also you put a disconnect for the tow bar light. Of course this will only work if you have a hitch receiver on your rig.

Kevo

That's a really good idea. Yep, have a receiver and could easily mount a plug fore and aft. I think I'll go this route if nobody chimes in with a simple way to tap into the stock wiring.
Appreciate it!

 

[kevos37]

It was a simple way to get the job done without intruding on the tow vehicles wiring.

One word of caution ..... Once you disconnect the tow rig remove the light bar. Unfortunately my right light was located close to the exhaust. When we were at Yellowstone NP I was a little too excited to get out and about and neglected removing it. At our first stop I had walked around back of the vehicle and saw the plastic housing was starting to cook away. Nothing that Gorilla tape could not fix. LOL

 

[shipmag]

Coolerman could probably modify the harness to fit any year may be. But cant speak for him.

 

[Coolerman]

On pre-1974 trucks it's a bit easier. You simply unplug the rear chassis harness at the firewall and create a jumper harness between the 4 pin plug on the towing vehicle and the 2 male plugs on the rear chassis harness that have the park, turn/brake light wires. No converter is needed for this. if you have a truck built after 9/1973 you must use a 2 to three wire converter between the towing vehicle and the FJ40 due to the FJ40 having separate turn signals.