I usually tap the rear lights, and just hang the 4 wire out the trunk when towing and stow it under the carpet when not using it, doesn't pinch the wire much at all and works pretty good!

 

I kind of want to build my own hitch that is super low profile and much tighter to the bumper... But finding a flat-bar hitch receiver would be an issue....
I also want to build and ultra-lite aluminum trailer with an air suspension to haul my bikes around.

Basically this with bags and big enough for 2 bikes:

IMG_4657 by Dominant Engineering, on Flickr

 

Now we are modding trailers???? It looks nice though.

 

moddinhg? I'm taking about fabricating it from scratch!
Plus making the trailers height adjustable with bags makes loading and unloading bikes off it easier and safer.
If you have car on bags with a trailer, going up and down with the cars height is going to drastically change the angle and pitch of the trailer, which chafes the tongue weight.

 

Plus it would look very cool.
That looks like a fun project.

 

Wow, thanks for all the replies, guys, this thread kinda took off. I think I'll be ordering my hitch today, probably the Draw-tite. I too was wondering about the wiring since Lexus hadn't imagined that this would ever be used for towing, though I thought someone mentioned the Lexus Europe had a factory hitch available. If so, I wonder if there is a factory piece for the lights that can hook up and plug in somewhere directly into the harness without having to do any pinch splices or running wires back from the fuse block? Looking forward to seeing others going thru this project as well posting their successes, I plan on doing it with mine too.

 

Lexus (Toyota) offered a hitch for the LS400 through their dealers in many countries around the world but not in North America. Actually, through, the Lexus dealer from which I bought my first LS400 in 1990 offered an aftermarket trailer hitch but I'm pretty sure they subcontracted the work out.

There is no trailer light wiring harness from Lexus for the LS400. Even if there once was, it would have have been an "accessory" and would have disappeared from the accessory catalog a long time ago.

The trailer lights really should be powered from the underhood fuse box or from the car battery. I powered the trailer lights directly from the tail lights of my 1990 LS400 and the trailer lights drew too many amps for them to operate reliably - the tiniest bit of corrosion on the trailer light connectors would cause them to dim.

I think there are still directions on the Lexus Europe service site (similar to the North American "techinfo" site") that show running the trailer light power cable through the interiors of Lexus sedans and then into the engine compartment - a pretty big job. It was quicker to have my mechanic ran the power light for the trailer light kit on my 2000 LS400 out an existing hole for an ABS cable in the trunk and underneath the car to the engine compartment fuse box. He did a great job of hiding the power wire under the car since I can't find it. There is a terminal on the left side of the engine compartment fuse box that is perfect for powering trailer lights; I used the same terminal to power the two extra horns on my 00 LS through an aftermarket relay. I've supplied a photo of this terminal in past threads.

 

J.
Thank you for that info.
That helped me decide to go ahead and run a red wire under the car and look for that fuse terminal.
I want it hidden also. Out of sight, out of mind.

 

I should tell you that some people have called me crazy when I said on car forums that my trailer light power wire was underneath the car. Some speculated that the power wire would be exposed to damage from debris and weather but these people were sometimes SUV owners who turn their vehicles off-road. But there have also been stories about interior fires caused by frayed trailer light wires running through vehicle interiors.

Regardless of which way you do it, be sure to use an in-line fuse near where you connect the power wire to the battery or that engine compartment fuse box terminal I mentioned. There was plenty of room under the fuse box cover for this in-line fuse and even for the relay for my extra horns.

 

You may well be crazy Jim. But I will heed your advice and make dang sure that the line is current protected by a fuse. I have everything else hooked up and tested, so just need to provide the power source.

 

You could also just run a single power wire to the trunk, or tap off you aftermarket sub amp for power, and use low-load relays to tap into your taillight harness and have the taillights trigger clean high-powered sources to the trailer.

 

Thanks, I will check it out and see what is best , then post what I did.

 

I'm wiring up lights to pull a trailer on my '97 LS 400. I am running power from the battery. Anyone know which is the "Turn signal? Running lights? Brake light?" on the LS400 tail light harness?
(I know I can test them, but there's so much info on here, I'm sure someone already has it figured out. Thanks.

Here is a pic of the wires coming off the tail light.... Thanks.