wire code for wiring a trailer...? (1 Viewer)

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K
Connect as follows:
Truck Wire ColorConverter Wire Color
Green (Park/Tail)Brown
Green/White (Brake) Red
Green/Yellow (Right Turn)Yellow
Green/Black (Left Turn)Green
White/Black (or ground to frame)White

Mark:

It looks like you have the Curt’s RIGHT and LEFT swapped. I’ve never used this Curt Convertor and the OP’s picture was taken from an angle that causes the wires to not align with the description.

Turn signals should be:

Green/Yellow (Right Turn) Green
Green/Black (Left Turn)Yellow

88FAFBBF-C962-4909-81F3-B469263F6799.png
 
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Yes, the wiring of the curt is not the issue........it is what wires in the truck harness go to the curt...?
I know white/black is the ground and green yellow is signal/brake.....green/white is signal brake....brown is running lights....
but I have a RED/black .......? and another solid Green.......?
I can now get running lights and brake lights.......

Paul: wire as @Coolerman stated, except, wire turn signals like this:

Green/Yellow (Right Turn) Green
Green/Black (Left Turn)Yellow

The only Red/Black (RB) I can find on the schematic I included above, is the cigarette lighter... shown in the middle of this fragment:

D467995D-C433-4C82-ACED-A5216B183387.png



I’ve never used the Curt 5-4 wire convertor, I have used the wiringproducts “3-wire to 2-wire Tail Light Converter”
( 3-wire to 2-wire Tail Light Converter - WiringProducts, Ltd. )

The concept is the same... you are converting:
2 wires (a right turn signal (Green/Yellow) and a stop light (Red)) to a single wire (Green) and
2 wires (a left turn signal (Green/Black) and a stop light (Red)) to a single wire (Yellow).

This allows the separate FJ40 stop and turn signal bulb’s functionality to be handled by the single (combination) bulbs on the trailer.

I used the the 3-2 wire converter to accommodate the same functionality between my FJ40 and my Hitch Cargo Basket lights.

I also used the same 3-2 wire converter to wire the opposite way (2-3), to split out my Tundra (single bulb) stop light, to the appropriate stop light on my FJ40... for when I tow the 40.

I hope this helps.

BTW WHEN YOU SAID, “wires in the truck harness go to the curt...?”, truck referred to your FJ40... YES??
 
Your "before" photos are better than what someone did to my FJ40 back in the day. I've got it cleaned up now but don't really want to splice in something new...

44’s rear harness was also chopped to pieces by someone who had no concept...

When Mark built my new rear harness, I had him pigtail for trailer lights and also for towing 44 with my Tundra... I just had to add the 3-2 wire converters.

It’s a really clean wiring job now!!

Just a thought...
 
@Coolerman, do you offer some type of plug and play adapter for the Curt 56496? Wiring those things should be pretty easy, but just wondering. I thought I remember reading something about it once.
Yes, I have a stand alone plug and play tow harness that has the Curt 56496 built in. This harness plugs in between the rear chassis harness and the main cowl harness. The converter is under the hood so is protected from abuse. Good for trucks from 9/1973 to I think 5/1978. That is when Toyota started using those weird 6 pin and three pin connectors for the tail lights and rear chassis harness. They are no longer available so I can't build a plug and play tow harness for anything after that.
 
Yes, I have a stand alone plug and play tow harness that has the Curt 56496 built in. This harness plugs in between the rear chassis harness and the main cowl harness. The converter is under the hood so is protected from abuse. Good for trucks from 9/1973 to I think 5/1978. That is when Toyota started using those weird 6 pin and three pin connectors for the tail lights and rear chassis harness. They are no longer available so I can't build a plug and play tow harness for anything after that.


Did the rear harness plugs change before 1/79? I show multiple changed from 9/73-1/79 in the rear harness. 9/77-1/79 being the last one. Because of risk of forest fires moved most my parts including wiring harnesses to another location. Have a 80 harness and couple 11/78 harnesses. Do not remember the different size pin connector.

I have a M416 and trailer made from a seventies pickup. Working on a way separate the brake light for the Toyota trailer and have the change automatic depending on which trailer is plugged in.
 
Yes, I have a stand alone plug and play tow harness that has the Curt 56496 built in. This harness plugs in between the rear chassis harness and the main cowl harness. The converter is under the hood so is protected from abuse. Good for trucks from 9/1973 to I think 5/1978. That is when Toyota started using those weird 6 pin and three pin connectors for the tail lights and rear chassis harness. They are no longer available so I can't build a plug and play tow harness for anything after that.

Is it listed on your website? I’ve looked off and on and never could find it.
 
Verified that 6/78 was when they went to the weird 6/3 pins connectors for tail lights and the main cowl to rear chassis harness connectors.

Also I do not have many products that I build listed on my web site. Why? Most of them are low volume sellers so I have never seen the point of listing them there. Another reason? I am so busy, that if I did list those products, I would not be able to build them in a timely manner. I guess I need to outsource my side work to China or somewhere... :cool:
 
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Paul: wire as @Coolerman stated, except, wire turn signals like this:

Green/Yellow (Right Turn)Green
Green/Black (Left Turn)Yellow

The only Red/Black (RB) I can find on the schematic I included above, is the cigarette lighter... shown in the middle of this fragment:

View attachment 2062427


I’ve never used the Curt 5-4 wire convertor, I have used the wiringproducts “3-wire to 2-wire Tail Light Converter”
( 3-wire to 2-wire Tail Light Converter - WiringProducts, Ltd. )

The concept is the same... you are converting:
2 wires (a right turn signal (Green/Yellow) and a stop light (Red)) to a single wire (Green) and
2 wires (a left turn signal (Green/Black) and a stop light (Red)) to a single wire (Yellow).

This allows the separate FJ40 stop and turn signal bulb’s functionality to be handled by the single (combination) bulbs on the trailer.

I used the the 3-2 wire converter to accommodate the same functionality between my FJ40 and my Hitch Cargo Basket lights.

I also used the same 3-2 wire converter to wire the opposite way (2-3), to split out my Tundra (single bulb) stop light, to the appropriate stop light on my FJ40... for when I tow the 40.

I hope this helps.

BTW WHEN YOU SAID, “wires in the truck harness go to the curt...?”, truck referred to your FJ40... YES??


Thank you for getting back....
my Truck is a BJ42...24 volt diesel, but, the wire harness is 12 volt.....
I was following the schematic and found some of the wires (color codes ) did not match and this is when the frustration started
I now have running lights, break lights and my signals are crossed, so......
I am going to change that at the connector.
I ordered 2 new front signal running lights........so, I have to connect those to make sure all the wiring does what it should...
thank you for your help
 
@Coolerman - Great info as usual. I do have a slight variation to ask about. My trailer has LED lights all around so I suspect voltage drop and dim lights won't be an issue if I go w/ a non-powered convertor? If so - is there a non-powered convertor you would recommend? Not opposed to DIY soldering diodes inline and shrink wrapping either.

Truck is a 12/1978 build. Trailer use is very limited but need the basics.

Thanks -
 
I tried LED's ( the 12-24v )......did not work for signal. Read that you have to put a Diode in between the signal light and line......otherwise no signal.
But, they are bright.....really bright. i just left the wiring that gave me one signal light, and both running and brake lights.......to frustrating to find the other signal issue. I also went with 24v bulbs.......so, all good for now
 
Did you try @Coolerman for his LED flasher relay? Since it also helps with ground issues, I’m a huge fan of it. FYI, he also makes trailer harnesses as seen below. Mine works great. No splicing either.

Scroll to the bottom of the page on Flasher/Relays, link below.


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That harness looks like exactly what I need…if the clips are 1981 style…
Thanks.
JDS
 
Coolerman built mine for my 1974. It plugs into the factor wiring harness in the engine bay. You can hit him up at his website and see if he still does these. He can make things year specific. Like everything he does, it's a quality piece.

 

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