24 volt trailer wiring to 12v Using Relays Diagram

[skinnyR1]

Thank you Jim for the reply. I do understand the diagram. I think.

The issue is with the brake vs tail light signal and the fact that they use the same bulb.

I think its only an issue if you pull the brake light signal from the brake controller. If you use the plug signal you will be ok. The truck cuts out the brake light when you have the turn signal on. If you use the diagram as shown, the brake signal will over ride the turn signal, and you won't get a signal with the brake pushed.

I think talking it all out makes sense now. Thanks.

 

[bchauvette]

I'm sure this works but as usual I'm confused. I was under the impression that the tail lights where at diminished brightness via a resistor and that the directionals would put full voltage for full brightness on that particular side.

Is it that if the brakes aren't on the directional pulses full voltage to that side and if the brakes are on it pulses the "on" brake voltage?

 

[skinnyR1]

I'm sure this works but as usual I'm confused. I was under the impression that the tail lights where at diminished brightness via a resistor and that the directionals would put full voltage for full brightness on that particular side.

Is it that if the brakes aren't on the directional pulses full voltage to that side and if the brakes are on it pulses the "on" brake voltage?

I continue to ponder this.

Mine don't go dim, they flash on and off completely when using the turn signal.

In looking further into this, tapping into the brake light switch directly vs at the plug both have their downfalls. At the plug, all you have is 1. service light 2. right turn/brake and 3. left turn/brake. If I were to tap into that pin at the plug, I would then get the same turn signal pulse at the brakes when using the turn signal.

The alternative, which is in Jim's diagram, is not have a turn signal when pushing the brake.

In order to bypass this, when incorporating a brake controller, you will use the brake controller only for the electric brake signal. And just like Jim's diagram, you need to tap into the brake signal at the switch, and not at the plug. So you will effectively be using Jim's diagram, except you don't need the brake light signal from the controller since the brake light and turn signal lamp is one in the same.

 

[skinnyR1]

I think this is what I am after. That second brake signal is unnecessary as our trucks share the brake and turn signal. But I am going to move the brake relay into the box, so that it isn't switching on and off all the time when I don't have a trailer.

I will have a 4 wire plug that disconnects from the box, so that the box is removable. The 4 wires will be the 24v brake signal, 12v Supply, 12V brake signal to the controller, and 12v Electric brake signal back to the plug.

I will have a female rv plug hanging out of the box, as well as the NATO plug.

 

[skinnyR1]

More thoughts.....

The 24V relay from the brake switch might not even be needed at all. Instead, I believe you can tie the left turn and right turn relay outputs onto another leg, and route it back to the controller. This leg will get a signal from the brakes no matter what since it is connected to both lights, and it won't be interrupted by the flashing signal.

I will put together another schematic later.

 

[skinnyR1]

Edit: Another incorrect diagram. Back to the drawing board....

 

[skinnyR1]

Here's what I have. Pretty much what jimk posted except the brake relay is in the box.
This way I can take the box on and off as needed. The NATO plug and female rv plug will hang off the box, and a separate four way connected is needed for the 24v brake, 12v supply, 12v brake and 12v electric brake signals.

 

[lucite]

This is almost exactly what I was looking for but I was wondering what kind of dc/dc converter would I need to step down the 24v-12v (wattage and amperage).
Thanks.

 

[skinnyR1]

I used a vanner equalizer. They commonly come off of transit buses and are sold used on the auction sites cheap. I think I paid $70 and its good for 60 amps.
There are other step down options though, if you intend for low draw.

 

[lucite]

I'm not exactly sure what the draw would be for the applications I intend to use it on but it be ranging from a flat deck to a pull behind camper.

 

[skinnyR1]

I think an electric brake controller requires 20 or 30 amps maximum.

 

[lucite]

you wouldn't happen to have a part number/model number for that equalizer would you?

 

[skinnyR1]

I believe mine is a vanner 60-50a