[Hillclimber]

Thought I would post my home made adapter, light controller or what ever you might call it.
I searched for a 24volt model but only came up with a couple and they only send 24 volts to the trailer, no good if you hook up your buddies trailer that hasn't got LEDs. 😆 changing bulbs every 5 mins isn't fun. Hahah.

This cost me about 42 dollars cad. All items were bought online. Mostly ebay.
1x standard trailer wire adapter 12 volt. Any 4 to 3 adapter will work. I bought a Reese.
4x 24 volt relays. Mine are 40 amp but anything above 10 should be lots. It's important that they can take 24 volts. Or they could over heat when on for long periods of time.
4x relay wire harness.
1x 24v-12volt dc converter. Prefered water proof. I bought a small 3amp one for 6 bucks. Fully sealed.
Soldering iron

On tow vehicle side. Each wire will go from your truck lights to a relay at 24volts then relay opens up to send your new 12volt signal to the trailer adapter, adapter then sends the signal in 12 volts to the trailer lights. Your grounds will be shared for both 12 and 24 volts. So no worries.
Brown yellow red and green. (Standard trailer colours)
Each relay will recieve input from your truck 24volts to trigger relay and switch 12 volts to the trailer adapter.
Using the standard numbers on a relay...
87 will be 12volt out to trailer adapter.
30 will be 12volts in from 12volt converter
85 will be common ground (truck metal)
86 will be 24 volt switch from your trucks lights.
Your relay will have 24 volts on one half and 12 on the other. You can run a aux line straight from 12volt converter to your trailer harness, no relay required.

 

[Hillclimber]

Adapter and converter

 

[Hillclimber]

Finished product.

 

[Twinotter600]

Good stuff! If you have the wiring diagram post it up please. Lots of us could use this. I cheated with 12-24volt LEDs in the trailer and rear vehicle lights. I proper converter/connector is better. Are you able to post up where you purchased the bits?

You in Cold Canada?

 

[Hillclimber]

I don't have a wiring diagram. But it should be pretty simple using the numbers provided and the relay because they match up.
Everything is avail from China on ebay pretty cheap. I'll see if I can post up links to it.
On a side note I'm going to tie my brake controller into it aswell using the same process. Should be able to hook up to any trailer no problem now. ��

 

[mattym]

Just a quick question - the dc to dc converter is rated at 36W, 3A. If I have a trailer with normal bulbs which would be 2 brake lights at 21W, indicators at 21W, and park lights at 5W, wouldn't you end up overloading and burning out the converter? There would be a common scenario when you have brake lights on while indicating which would have a load of 63W, 5.25A.

 

[Hillclimber]

Yah I knew it was going to be close for power. But the brake lights (in Canada anyway) are the indicators. So if u have the brakes on and indicate the indicating brake light goes off. So even if the running lights were on its only brakes and running lights. The converter is 36wats continuous power at 12 volts but can handle more for short periods. Plus I use led on all my trailers. I'll see how it goes long term. Good so far though.

 

[Canuck]

Nicely done. Going with the higher amp DC-DC reducer is not pricey. I bought four 23 amp (20 amp continuous) of them from Hong Kong a few years ago. Think I paid about $60 total - including shipping. They came regular mail and did not get nailed for import duties and brokerage fees. Twinotter600 gave me the link. Can't find it now.

 

[88Safaride]

I have all the parts, not sure how to hook it all up

Pardon me, I have all the parts you recommended, but I feel as though I am in over my head with the info I've got. Here are some questions, however relevant.

Where do I splice into the existing wires, behind the tail light?
Do I run a separate power chord to and through the converter?

mainly I'm not sure how the 24V-12V converter wires in and where..

Thanks,