Trailer Wiring for Deuce

[NorthWoodsDuce]

I need to put wiring on my deuce for civil trailers. I searched and did not find any comments from anyone that had previously done this. Obviously I need 12v for civil trailer... but don't want to put extra switches in cab for all trailer lights. Friend put converter in cab with switches for brake, turn and tail lights.. don't want that.. anyone have better ideas

 

[Barrman]

Pretty much, you can modify the truck in some way or modify the trailer. The trailer is probably the easiest to mess with. Just change out the bulbs. You could also just run the 12V bulbs and carry a few spares. If you are doing day time driving, you probably will last a few days without blowing a bulb in the trailer.

Doing something half way on the truck will lead to grief. If your rear lights are 12V and the fronts are 24V, not much good will come of it.

Now, the entire truck lighting system will work just fine on 12V. This includes the solid state blinkers. You have to change all the bulbs out though. I would not suggest this route either.

A lot of people have simply run dual lights on their trailers. One 12V system and another 24V system. It might take you an afternoon to wire it up so it looks nice, but that is probably your best bet if the trailer is going to be pulled behind both voltages on a regular basis.

 

[El_Guapo]

In theory it should be possible to use resistors to pull the voltage down from 28v to 14v. They could easily be wired in between the mil trailer plug to the civvie plug. However, it would require a fairly large amount of homework and calculation before selecting the proper resistance.

 

[DavidB]

Change out the trailer lights to multi range LED (12-24-36) local truck supply has them here .The price is getting better and they are brite. The biggest problem would be electric brakes. Old cut cords make good pigtail adapters.

 

[devilman96]

Ditto on the LED's... Being that its civilian I would pursue David's suggestion and hit the local truck light places.

I carry the Mil spec 12-36V LED light sets http://odiron.com/store/product_info.php?cPath=28_19&products_id=591 but they are not exactly the cheapest route for a civilian trailer set up.

 

[ken]

If you go with the led's get yourself a trailor plug harness from front line or saturn. Not sure but i think old iron has them also. Then you don't have to cut the truck wiring and the metal tags will tell you what goes where. Or you could get some mill tail lights and have both civi tail lights and mill ones. Complete with blackouts.

 

[MikeON]

I put a 12v, 15a converter on the firewall. Then I have 4 relays wired into the truck's left turn, right turn, tail, and brake light. The relays switch the 12v power to the appropriate leads in the trailer harness. Got a 4 conductor harness at NAPA, which goes from the relays in the cab to a regular 7-pin trailer receptacle at the back. This way, the relays are under the dash and out of the weather.
The relay on the brake light signals the Tekonsha Prodigy brake controller to apply the trailer brakes.
The relays are 12v, so I put a 100 ohm resistor on the 24volt side of each.
So far it is working very well. I burned up one 12v converter while testing the brakes on level road - I had turned the Prodigy on full blast. The converter is supposed to be overcurrent protected, so the seller (on ebay) gave me a new one. Because of that, I may get a larger converter, but if you aren't planning for electric brakes, the small one should be fine.
I chose this path instead of LEDs or bulb changing, so I can pull different trailers with different vehicles and not have to worry about voltage differences.
Mike

 

[ida34]

How may axles had brakes on your trailer. I was thinking that more axles would pull more current. I am going to check the draw of my trailer before I put together my set up. I got an old large multi path relay off ebay and I have a 10 amp converter. I had thought about putting a 12 volt battery on the trailer and using the converter to charge the battery only. I would then draw all 12 volt accessories, lights, and the brake controller off the battery. I figured this would lessen the effects of the trailer brake controller surging power when the brakes are applied. Any of the electrical guys please chime in as to whether this sounds like it will work.

 

[MikeON]

My trailer has 2 axles, both with brakes. The battery between the brake controller and the 12v converter would probably be a good idea - wouldn't have to be very big, and would give a measure of safety in case the converter fails.

 

[JRBAMATEX]

See this thread. Lots of good info.

http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=10734&highlight=

 

[NorthWoodsDuce]

I have 5 different trailers, so light bulb swapping is not an option. There has to be a better option... more research I guess.

 

[rmgill]

Voltage converter box in the bed. Relays to function your tail lights. Plug into the 12 pin on the deuce, connect the trailer plug to the box. If you need electrical brakes, you can set it up in the box to do the same but size up the DC-DC converter to handle the load from the brake controller.

 

[NorthWoodsDuce]

There is a lot of things I am good at... BUT automotive electrical is not one of them rmgill....hooking up relays and converters... hrmmm.. I can see a flaming deuce in my future!! Any chance of diagram or drawing of what wires go where?

thanks everyone for your input!

 

[devilman96]

I've been considering building some of these but making them "plug and play" is pricy in its self due to the parts required.

A 24-12V DC/DC transformer in a high enough amperage to support the braking sysem + Mil cable + plugs + relays + etc, etc your easily in the $300-400+ dollar range.... Even though I see this topic come up about ever month or two very few would spend the cash on such an item.

 

[clinto]

I would (spend the cash)...

IF....

I could buy a box that had the following:

A mil style trailer plug that plugged into the receptacle on a military vehicle
On the other side of the box, 4, 6 and 7 pin connector receptacles so any kind of trailer can be plugged in
A gladhand to connect the box to the towing truck, that converts air pressure to an electrical signal for electric trailer brakes
Since the box will already be knocking down 24 volts to 12, maybe it could have a 12V power port on it, for whatever......

You could either mount it with some crazy heavy duty mangnets, so have some loops on it so you could ratchet strap it to any trailer......

This box would allow, say a Deuce, to pull ANY civvy trailer, from a small landscape trailer, to a heavy equipment lowboy.

For that, I'd pay a pretty fair amount of $

 

[devilman96]

I would do everything but the air... You don't need it as the brake circuit would take care of what you needed to, having both would be totally redundant unless I am missing something your saying.

 

[clinto]

If your trailer had electric brakes, you wouldn't need a trailer brake controller and if your trailer had air brakes, you just plug the trailer's glad hands straight into the tow vehicle-saves you from needing a separate trailer brake controller int he vehicle

 

[Dhallftworth]

Digging this up from the past... Clinto, did you ever end up building a box? Pics?

 

[clinto]

Digging this up from the past... Clinto, did you ever end up building a box? Pics?

Yes/no.

I've designed all of the box and built about 80% of it. Last thing I have to do is install the self diagnostic system (long story) and then paint the box. I then have to strip my deuce interior, paint it, install the M44A3 cab brace so I can upgrade to the M44A3 3-point shoulder belts. Once the cab interior is done, I can mount the box on the back wall of the cab.

I'll start a thread once I'm done, but the short version is:

All new cannon connectors.
Cannon connectors are mirror imaged so you can't hook them up wrong in diagnosis/servicing/repair
Each power circuit is individually fused
All wires are 14awg, other than the 12V power supply to the fuse box.
12V power comes to the box from a stand alone 12V battery that's charged by my HMMWV 12-24 dual output alternator
This box has a provision for a 12V electric trailer brake controller - the small 4 pin cannon connector send the 12V supply and 12V trigger to the controller and the brake voltage comes back into the box via the third wire and is sent down range to the civilian 7 pin connector at the back of the truck.
There is a provision for fused 12V power at the dash as well, for cell phone charging.
All electricals in the box are mounted on a piece of plastic so it can be removed for easier servicing or if the box is damaged.

When I posted this a dozen years ago, I thought a box that was mobile between multiple trucks would be the best idea. But the difficulty of getting trailer brake functionality into the equation was so high that I settled on a permanent box in the pulling truck, which means if you own multiple trucks you have to build multiple boxes. If all you need is the lights on your civilian 12V trailer to work with your military truck, XM381.com builds good converter boxes that do this.

Here's what I have so far:

 

[Eliteweapons]

There are companies out there that make conversion boxes now but they are expensive.