Sephirothq
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Here is a writeup I did for trailer brakes. Feel free to comment. No pics yet.
12 volt brake controller on a 24 volt system
Parts needed
1. Quality brake controller (using a proportional controller so you don’t have to cut into the hydraulic brake system)
2. 24 volt to 12 volt voltage converter (You need at least 3 amps per wheel with brake, 4 brakes is 12 amps, not including the brake light bulbs, so at least 20 amps, preferable 30 amps)
3. 24 volt relays x 4 (these are the small black boxes, 24 volts and a ground in to complete a circuit)
4. wire
trailer 4 wire approx 6 feet,
#12 wire blue, #10 wire red, enough to run from the inside of the cab to the trailer port on the truck, You length will vary with your wheel base.
#8 wire red and #8 wire black enough to run from the battery box to your voltage converter, again different length depending on where you mount your voltage converter.
#14 wire, black, red, blue and white, these are the colors of the wires of the brake controller. You length will vary with where you mount your brake controller and where you have your voltage converter mounted. The black goes to the ground. Just pull it from your ground on your voltage converter, The blue goes to the #12 that runs back to the back of the truck, the white goes to your 12 volts on the voltage converter, and the red goes to a relays under the dash You have to add this detail to follow)
16 female terminal ends for #14 wire
1 splice terminal
wire nuts for 5 #14 wire
Water tight enclosure
6 foot of trailer wire for 6 wires at #14 wires.
7 pole truck side trailer connector
flat 4 pole connector trailer and vehicle side
round 4 pole connector trailer and vehicle side
nato trailer connector (the one that plugs into the truck)
Your parts list might vary
Inside the cab.
The first thing to do is to find a place to mount your trailer brake controller, your voltage convert, and one of the 24 volt relays. Always mount your boxes first.
Run the red and black #8 wire from the battery to the voltage converter,
From the 12 volt side three wires will run from here. One #10 to the back of the truck this is your 12 volt constant for the trailer, one #12 to the white side of the brake controller, and the last #14 to the 24 volt relay.
From the ground side of the voltage converter run #14 wires to the brake controller and relay on the ground side.
From the relay run a #14 wire to the brake light switch, Run a #14 wire to the red side of the brake controller
On the brake controller there are all four wires connected, the black is to the ground on the power converter, the red is to the relay, the blue is running to the back of the truck and the white is going to the 12 volt side on the power converter.
Running to the back of the truck is a blue brake signal wire and a red constant 12 volt source.
Back of truck
I wanted the system to be hidden for the most part.
Find a place to mount your water proof enclosure, Make sure to rubber mount if you take your truck off road.
Run the two blue and red wires into the box, connector your NATO trailer connector and run the grounds, left, right, and running lights into the enclosure. Mount your 7 pole connector and run the wires into the enclosure.
I have a 4 pole flat connector on a nato trailer plug so I just used that, I can use it for other jobs if needed, ie connecting to a set of magnetic lights.
I also used the 4 pole round connector to the wires that run to the back of the truck to the enclosure box incase I needed to remove the box. If you do this run at least two of the 4 poles on the constant 12 volts.
Inside the enclosure
You will use 3 of the 24 volt relays here.
The grounds will go to each of the relays, and also to the 7 pole connector
The constant 12 volts will go to each of the relays
The nato trailer wiring for the left, right turn and the running lights will go to each of the relays
The other three sides from each of the relays will go to the 7 pole connector
Run the blue brake signal wire to the 7 pole connector and the 12 volts constant to the 7 pole connector.
Plug in your trailer and check your lights and brakes.
You should have only 12 volts on all channels going to the trailer.
12 volt brake controller on a 24 volt system
Parts needed
1. Quality brake controller (using a proportional controller so you don’t have to cut into the hydraulic brake system)
2. 24 volt to 12 volt voltage converter (You need at least 3 amps per wheel with brake, 4 brakes is 12 amps, not including the brake light bulbs, so at least 20 amps, preferable 30 amps)
3. 24 volt relays x 4 (these are the small black boxes, 24 volts and a ground in to complete a circuit)
4. wire
trailer 4 wire approx 6 feet,
#12 wire blue, #10 wire red, enough to run from the inside of the cab to the trailer port on the truck, You length will vary with your wheel base.
#8 wire red and #8 wire black enough to run from the battery box to your voltage converter, again different length depending on where you mount your voltage converter.
#14 wire, black, red, blue and white, these are the colors of the wires of the brake controller. You length will vary with where you mount your brake controller and where you have your voltage converter mounted. The black goes to the ground. Just pull it from your ground on your voltage converter, The blue goes to the #12 that runs back to the back of the truck, the white goes to your 12 volts on the voltage converter, and the red goes to a relays under the dash You have to add this detail to follow)
16 female terminal ends for #14 wire
1 splice terminal
wire nuts for 5 #14 wire
Water tight enclosure
6 foot of trailer wire for 6 wires at #14 wires.
7 pole truck side trailer connector
flat 4 pole connector trailer and vehicle side
round 4 pole connector trailer and vehicle side
nato trailer connector (the one that plugs into the truck)
Your parts list might vary
Inside the cab.
The first thing to do is to find a place to mount your trailer brake controller, your voltage convert, and one of the 24 volt relays. Always mount your boxes first.
Run the red and black #8 wire from the battery to the voltage converter,
From the 12 volt side three wires will run from here. One #10 to the back of the truck this is your 12 volt constant for the trailer, one #12 to the white side of the brake controller, and the last #14 to the 24 volt relay.
From the ground side of the voltage converter run #14 wires to the brake controller and relay on the ground side.
From the relay run a #14 wire to the brake light switch, Run a #14 wire to the red side of the brake controller
On the brake controller there are all four wires connected, the black is to the ground on the power converter, the red is to the relay, the blue is running to the back of the truck and the white is going to the 12 volt side on the power converter.
Running to the back of the truck is a blue brake signal wire and a red constant 12 volt source.
Back of truck
I wanted the system to be hidden for the most part.
Find a place to mount your water proof enclosure, Make sure to rubber mount if you take your truck off road.
Run the two blue and red wires into the box, connector your NATO trailer connector and run the grounds, left, right, and running lights into the enclosure. Mount your 7 pole connector and run the wires into the enclosure.
I have a 4 pole flat connector on a nato trailer plug so I just used that, I can use it for other jobs if needed, ie connecting to a set of magnetic lights.
I also used the 4 pole round connector to the wires that run to the back of the truck to the enclosure box incase I needed to remove the box. If you do this run at least two of the 4 poles on the constant 12 volts.
Inside the enclosure
You will use 3 of the 24 volt relays here.
The grounds will go to each of the relays, and also to the 7 pole connector
The constant 12 volts will go to each of the relays
The nato trailer wiring for the left, right turn and the running lights will go to each of the relays
The other three sides from each of the relays will go to the 7 pole connector
Run the blue brake signal wire to the 7 pole connector and the 12 volts constant to the 7 pole connector.
Plug in your trailer and check your lights and brakes.
You should have only 12 volts on all channels going to the trailer.
