UZJ100 Trailer Wiring - Need Primer (1 Viewer)

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I've been steadily wrapping up some of the smaller projects on the 100. One of the left over ones is wiring it to prep for the expedition trailer. I've been reading up on threads and it appears folks have mixed reviews on the OEM connector; I'm pretty convinced I'm going to go with an aftermarket product. Does anyone have any recommendations? I don't see anything available that's specific to a 1999 UZJ100. I'm specifically looking for a 7-pin connector, something that allows me to tap into the OEM wire harness rather than butcher it.

Also, I was thinking of cutting a hole into my 4x4 Labs to mount there; thoughts on this? I can also mount it behind it.

TIA!
 
The OEM connector has had a TSB or something on it, so that may be the issue you've seen. After the repair is made I haven't heard of any issues.

Aftermarket companies make connectors, but most of them are 4 pin. Do you need 7 pin? I thought the difference was if the trailer had it's own brakes. Here's Draw-tite's 4 pin connector:

draw_tite_t_connector.jpg


As for your bumper, here's a slick 4 AND 7 pin socket:

37185.jpg
 
The OEM connector isn't the problem. It's the OEM converter box that integrates the stop/turn/tail signals into the trailer standard. Mine blew out quick when attached to a trailer. A new aftermarket converter box is the way to go. Even better is an independent isolated converter (~$70) that attaches to the battery directly and protects the vehicle wiring.

Converter
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+ Connector/Adapter
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More pins without more source wiring does you no good. The OEM set up does not allow for trailer brakes, electrical charging or back up lights. You'll have to run these wires yourself even if you tap into OEM harness.

Trailer Wiring Code PDF

I recommend a good trailer place. One that does horse or serious RV trailers. Avoid U-haul ect...

There are some good threads - search for "brake controllers"
 
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Thanks, guys! I don't want to farm this out unless it's absolutely necessary, I'm pretty comfortable with electrical work and would like to keep it within a reasonable budget.

I don't *need* a 7-pin, but I do need more than a 4-pin, I want to run at least one extra wire to the trailer for a utility light. Should I just run a 4-pin standard trailer connector like the Draw-Tite above and then hook it to a 5-pin adapter?

The trailer is wired with standard 4-wire harness right now, but I also have a whole roll of the 7-pin stuff I picked up cheap years ago.
 
I don't *need* a 7-pin, but I do need more than a 4-pin, I want to run at least one extra wire to the trailer for a utility light. Should I just run a 4-pin standard trailer connector like the Draw-Tite above and then hook it to a 5-pin adapter?

If you are comfortable with electric than I recommend you wire in the isolated system for the 7-wire plug, like NMuzj100 recommended. Side benefits are that you will send a strong amperage line from the battery to the back of the truck, where you can tap in for other things, and you can tow just about anything without revisiting this issue. All the light splicing is next to the converter in the back of the truck. While you have the trim out, run a brake line wire to the plug too and leave extra coiled and labeled under the dash for your future brake controller.

I have several trailers, including a utility that only uses a 4 pin flat plug, but I have a plug converter that makes it easy to hitch up and go. The 4 pin plugs are cheap and difficult to use, in comparison to the 7 pin.

Buy some dielectric grease too - it ensures a good connection every time you plug in and keeps corrosion at bay.

Good luck.;)
 
I agree, go 7 pin and don't look back. Even if you don't use all the pins you'll have the industry standard and you can buy plug in adapters for 6 pin or 4 pin.
 
I agree, go 7 pin and don't look back. Even if you don't use all the pins you'll have the industry standard and you can buy plug in adapters for 6 pin or 4 pin.
This is the right way IMHO
I got the converter from a local trailer manufacturer, it plugs straight into the factory harness. The guy at the RV place told me there was no converter, if you get that find another shop. Here is a link to the one I used;
T-One Vehicle Wiring Harness with 4 Pole Trailer Connector 118365 : Trailer hitch bike rack and trailer hitches - etrailer.com
I cut the four pole connector off and wired it into a 7 pin receptacle to match my pop-up trailer, then perversely bought a 7 to 4 adapter to use with my utility trailer. :lol:
I still need to run a 10awg wire from the battery to the 12V pin. (With a fuse at the battery of course. )
 
The OEM connector has had a TSB or something on it, so that may be the issue you've seen. After the repair is made I haven't heard of any issues.

Trunk - we need to go to lunch.....I had my truck serviced under the TSB on the trailer wiring. Went to plug a trailer into it a month ago and the plug was dead. Started tracing it back up the line - the replaced trailer wiring converter shorted out again. Melted into a pile of goo. Called the Toyota dealer that serviced it - they told me tough luck - they only do it once.

Called the Toytota master tech neighbor - he suggested pulling all the old trailer wiring since there is obviously a short in it some where. I did that this week - replaced it all with new. Sucked. But trailer lights work for now. All though they seem to be blowing the fuse everynow and then. Wierd.

So I'm still having issues after the TSB.
 
Trunk - we need to go to lunch.....I had my truck serviced under the TSB on the trailer wiring. Went to plug a trailer into it a month ago and the plug was dead. Started tracing it back up the line - the replaced trailer wiring converter shorted out again. Melted into a pile of goo. Called the Toyota dealer that serviced it - they told me tough luck - they only do it once.

Called the Toytota master tech neighbor - he suggested pulling all the old trailer wiring since there is obviously a short in it some where. I did that this week - replaced it all with new. Sucked. But trailer lights work for now. All though they seem to be blowing the fuse everynow and then. Wierd.

So I'm still having issues after the TSB.

Toyota knows jack about trailer wiring. The original boxes were junk and the $300 TSB replacements have the same problem.

This is why the Isolated/protected system is a good idea. It prevents the trailer from feeding back into the expensive electronics of the truck. It would suck to lose the combination meter (The whole electronic dash) because of feedback from a trailer short. It's like plugging Christmas tree lights into a laptop.
 
hey all...hope everyone having a good weekend

i am pretty sure i had the TSB done last year was something about 'relay'???, will try to dig up my paperwork ...i also just installed the factory tundra harness that i got last year at the same time for an e-brake controller...i followed this thread https://forum.ih8mud.com/100-series...ler-brake-controller-late-100-series-tlc.html

...but sounds like this is a unreliable solution after coming to this thread today... do i need to get an isolated system??? i am planning on towing a pop up for a few weeks in july and would hate to fry my electronics...if i go the isolated route what exactly do i ask an RV/trailer dealer for??

thanks
the dude
 
If you ask that the system be isolated or protected then they will know what you want. It will connect to the battery directly instead of through the vehicle harness. The box should cost about $75 instead of $25.
 
forgot to add...i have an '03 ...in the FAQ it seems to be '98-99 TSB??

anyone with an '03 having any problems with factory set up?
 
forgot to add...i have an '03 ...in the FAQ it seems to be '98-99 TSB??

The newer 100s may all have the 2nd gen converter box. No TSB but they still fail.

Mine was replaced under the TSB. Within a day of attaching a trailer I had to replace it. Of course I assumed it had to the trailer since I had a new and improved converter and wasted hours trouble shooting the trailer wiring.
 
2006 Landcruiser

Mine is a 2006 FZJ-100, would the same connectors linked above apply to my truck? I did locate the connector behind the rear bumper, but none of the sites above shows a good close-up of the connector to confirm matching the pin configuration.

Thanks.
 
I'd go with a Modulite HD

I tow a big boat with a bunch of lights and installed an isolated Drawtite Modulite HD converter unit when the stock wiring converter went south, typical problem. Love the Modulite unit, works great. No issues with install or operation. Did a writeup a while ago....see below

Also, if you can get away with a 4-pin, that is how I would go unless you are wiring brakes or charging a battery. Stupid-simple is good when futzing around with trailer lights, and I've had problems with the round connector contacts bending over and far fewer with a simple 4-pin, just keep some PB Blaster or WD40 around to keep them clean and rust free.


https://forum.ih8mud.com/100-series-cruisers/232931-trailer-lights-modulite-hd-install.html

If you need brakes, I have had great experience with this controller on a trailer with brakes. This is an RF unit which DOES NOT require being tapped into the tow-vehicle lighting under the dash. The adjustment for sensitivity is done by pairing the RF controller with the trailer unit. Once paired, the controller just plugs into the accessory plug and brake sensitivity can be adjusted. We use this for a Boy Scout trailer with brakes that is towed by numerous parent vehicles. Wiring each would be a PITA.

http://www.tekonsha.com/product/default.asp
 
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Mine is a 2006 FZJ-100, would the same connectors linked above apply to my truck? I did locate the connector behind the rear bumper, but none of the sites above shows a good close-up of the connector to confirm matching the pin configuration.

Thanks.
A good trailer supply place will have the correct converter for your application. As I mentioned above if you go one place and they tell you different find another place.

I tow a big boat with a bunch of lights and installed an isolated Drawtite Modulite HD converter unit when the stock wiring converter went south, typical problem. Love the Modulite unit, works great. No issues with install or operation. Did a writeup a while ago....see below

Also, if you can get away with a 4-pin, that is how I would go unless you are wiring brakes or charging a battery. Stupid-simple is good when futzing around with trailer lights, and I've had problems with the round connector contacts bending over and far fewer with a simple 4-pin, just keep some PB Blaster or WD40 around to keep them clean and rust free.


https://forum.ih8mud.com/100-series-cruisers/232931-trailer-lights-modulite-hd-install.html

If you need brakes, I have had great experience with this controller on a trailer with brakes. This is an RF unit which DOES NOT require being tapped into the tow-vehicle lighting under the dash. The adjustment for sensitivity is done by pairing the RF controller with the trailer unit. Once paired, the controller just plugs into the accessory plug and brake sensitivity can be adjusted. We use this for a Boy Scout trailer with brakes that is towed by numerous parent vehicles. Wiring each would be a PITA.

Tekonsha Website - Leader in Electic Trailer Brake Controllers and Trailer Breakaway Brake Systems
I've been RV'ing for 25+ years and never had a problem with the round 7 pin connectors. :confused:

I wouldn't use WD40 or PB blaster on any electrical connector. There is a product called dielectric grease that is specifically intended to weather proof electrical contacts. It's great stuff, I've used it in many automotive and industrial applications.
 
A good trailer supply place will have the correct converter for your application. As I mentioned above if you go one place and they tell you different find another place.


I've been RV'ing for 25+ years and never had a problem with the round 7 pin connectors. :confused:

I wouldn't use WD40 or PB blaster on any electrical connector. There is a product called dielectric grease that is specifically intended to weather proof electrical contacts. It's great stuff, I've used it in many automotive and industrial applications.

Thanks for the correction on the dielectric grease, better solution no doubt. On the round connector, prolly just got a bad OEM unit on a new suburban, spent hours trying to get things aligned so it would work....
 

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