M931 to Civ. Lowboy wiring

[D6c]

I've got a lowboy trailer that I'm fixing up and thought I had the wiring worked out but now I'm not sure.

The trailer is older and is wired using only 4-wire cable with the frame acting as ground.
It's wired: Brown- Tail/Marker
Red- Stop
Green- Rt Turn
Yellow- Lt Turn
It has four rear lights, two acting as turn & two acting as brake, with all four as tail lights


After checking the output from the truck cable I find that the M931 uses
1 pin for tail lights
1 pin for Rt turn & Rt Brake
1 pin for Lt turn & Lt brake, with the flasher apparently creating the turn flash even when the brake is held down.

The trailer has all multi-volt lights so I was planning on adding a 12-pin socket to the trailer so that I can pull it with either civilian or military trucks without changing anything.

Two questions:
1) Is the trailer wired ok to work with civilian trucks? (don't have a truck handy to test it)

2) Is there a way to wire the 12-pin trailer socket to get it to work with the M931?

Hopefully there is a solution that doesn't involve completely wiring the trailer.

Thanks in advance

 

[The HUlk]

I'm thinkng you can connect it like this...

Truck running light pin to trailer Brown

Truck right turn/right brake pin to trailer Green

Truck left turn/left brake to trailer Yellow

Trailer Red not used.

 

[D6c]

Thanks, I'll sketch it out and see if I can make sense of it.

 

[Bandit02]

I run all 24V LED lights on my trailers

There is also a hot wire you can run to blue/aux pin that is ignition controlled for civvy ABS (if the ABS ecm is 24v) from the military wiring to a standard 7 pin connector. I cut the military truck side female plug off and installed a civvy 7 pin for my trailers. I use only 4 wires to power just like you mentioned,

 

[D6c]

I'm thinkng you can connect it like this...

Truck running light pin to trailer Brown

Truck right turn/right brake pin to trailer Green

Truck left turn/left brake to trailer Yellow

Trailer Red not used.

Looks like that's going to work. The lights will work differently between Military and Civ trucks but I don't think it will matter.
On the M931 the outside 2 lights will be stop, turn, & tail and the inside 2 will be just tail lights.

When hooked to a civ. truck the outside 2 will be tail/turn and the inside 2 will be tail/stop.

Since I have a mil. trailer socket on hand I think I'll just splice into the cable and mount it as a second connector next to the civ. nose box. It's an older trailer so I don't have to worry about power for any ABS

As long as the DOT is ok with this arrangement I should be good to go.

 

[lindsey97]

Civvy trailer red wire is brake.

 

[D6c]

Civvy trailer red wire is brake.

I will be using the red wire for brake on the Civ. plug, but since the brake & turn are combined on the Mil. plug I won't need to use the red wire on the mil 12-pin receptacle.

Got the wiring finished up.....looks like it will work well having two trailer receptacles. I thought about just making up an adapter plug but decided against it. This way any truck can hook up to the trailer without having to have a special cable or adapter.

Thanks for the help

 

[The HUlk]

I will be using the red wire for brake on the Civ. plug, but since the brake & turn are combined on the Mil. plug I won't need to use the red wire on the mil 12-pin receptacle.

Got the wiring finished up.....looks like it will work well having two trailer receptacles. I thought about just making up an adapter plug but decided against it. This way any truck can hook up to the trailer without having to have a special cable or adapter.

Thanks for the help

Glad it worked out for yah.