Trailer Lights Logic Circuit & Step Down Voltage Converter

[Stone]

There's a very simple way of utilizing a voltage converter and 4 24v relays to replicate the actions of an expensive 24-12v logic circuit.

The problem with JDM and some NA Land Cruisers is that we run a 24v electrical system while most things here run on 12v. Further, our tail lights have separate turn and brake signals while most trailers have the turn and brake lights combined. So, in order to utilize the common 4-plug trailer wiring, we need a logic circuit that will flash the appropriate turn signal while the brake lights are also activated (as in the situation of waiting at an intersection to make a left hand turn).

Further, most aftermarket logic circuits are made to work with 12v, not 24v...although an engineer at Hoppy assured me that their heavy duty model will work for both.

This method of using relays will assure that there is no heat buildup from using resistors to step down the voltage, and should be reliable providing that good quality relays are used (ie. Hella 87426).

You only need a few things:
-A good 24v-12v step down voltage converter already installed and in working order (ie. Solar Converter converter).
-Four Hella 87426 24v relays.
-Appropriate wiring, connectors, taps, and loom.
-A common 4-plug trailer connector.
-Basic electrical knowledge/skills.

Here's the diagram (thanks for the correction, Bruce):



I have not yet installed this on my vehicle...but I don't see why it shouldn't work. I will install mine as soon as I find a suitable protective case to house the 4 relays.

Note that the source wire for +12v power should be fused appropriately.

If anyone local here in the Lower Mainland BC is wanting this done to their Cruisers, but is not comfortable with doing the electrical work themselves, I would be happy to do the installation...although I haven't worked out the pricing yet. If you need a converter, G&S Cruiser Parts have them available.

Hope this helps solve some problems that some of you who would like to tow a trailer are struggling with.

Let me know what you think.

[lowenbrau]

I've looked at the diagram and the way I see it, that works fine if you always have you brakes on when you signal. I don't see how your signals will work when the brakes are not applied though. I'll keep looking in case I missed something.

[lowenbrau]

Try this version on (forgive the paint skills) and see what you think

[Stone]

Darn it...I knew it was too easy. I like your version better, Bruce. Thanks.

[crushers]

i have an email in to the makers of the 24-12V trailer light converter to see if we can get a deal on a quanitly order or not.
does anyone else have a use for these?
cheers

[The Dude]

Interested, maybe.

I just run all my trailers with three lights (well actually four because I like reverse lights on my trailers) and 24volts. It makes things very easy.

I guess a self contianed unit that could be transfered from truck to truck if needed would be nice, if the price was right.

[Radd Cruisers]

Good one for Tech Links.

[Greg_B]

Originally Posted by The Dude

I just run all my trailers with three lights (well actually four because I like reverse lights on my trailers) and 24volts. It makes things very easy.

When I get mine, it will be this way as well.

gb

[Red Herring]

Ya, im interested Wayne.

Stone... noob question, but where do you get the Hella relays from?

[Stone]

Steve: Lordco for me.

[crushers]

Originally Posted by crushers

i have an email in to the makers of the 24-12V trailer light converter to see if we can get a deal on a quanitly order or not.
does anyone else have a use for these?
cheers

okay,
i got a quote back from England and the converters are:

BATCH / ORDER QTY: DESCRIPTION UNIT PRICE£ STERLING(EX-WORKS)
1 – 10TAKEN IN1 BATCH E679 – MK2 (AVC19 – MK2) TRAILER VOLTAGE CONVERTERFOR VEHICLES WITHOUT ENGINE MANAGEMENT SYSTEM £49.00 EACH
11 – 50 TAKEN IN1 BATCH E679 – MK2 (AVC19 – MK2) TRAILER VOLTAGE CONVERTERFOR VEHICLES WITHOUT ENGINE MANAGEMENT SYSTEM £45.00 EACH
1 – 10TAKEN IN1 BATCH E805 TRAILER VOLTAGE CONVERTERFOR VEHICLE WITH ENGINE MANAGEMENT SYSTEM £49.00 EACH
11 – 50 TAKEN IN1 BATCH E805 TRAILER VOLTAGE CONVERTERFOR VEHICLE WITH ENGINE MANAGEMENT SYSTEM £45.00 EACH


so a group order will be $106 each vs $116 for a single order plus duty, taxes and shipping.
so if anyone wants one let me know and we can save on the shipping and an addition $10 for mor ethan 11 units (the last call recieved 3 responses so i kinda doubt i will get many more than that)
if interested email me at
wayne@crushersrule.com
cheers

[lowenbrau]

So this is a 4 to 3 wire (ie the stop and turn will be in the same bulb), 24 to 12 volt converter? Any more details? Pics? Wiring diagrams? USDA RDAs? MSDS sheets? Anything?

[crushers]

come on over, i am installing one right now...

[Green Lantern]

FWIW,
I bought a REDARC converter and they sell a trailer light conversion unit. The converter has worked well for me.

http://www.redarc.com.au/tl.htm

HTH
Happy Trails! N

[Red Herring]

Wayne,

Who is making those converters (web site)? Are they 3 or 4 pin... and lastly do they separate the tail/brake lights?

TY

[crushers]

http://www.eurogroup.gb.com/trailer_..._converter.htm

[Red Herring]

Ya... those look good Wayne.

[zander]

Wayne, Sending email now as i am interested...

[crushers]

so that is 5 interested , anyone else? i will probably put in an order the end of the month...

[Behemoth60]

For the record, I actually built one of these home made converters, using a design scribed on the side of a cardboard box invented by Bruce Loewen for me. Instead of using 24V relays, I used 12V relays with a 90 ohm resister to cut the signal voltage to the relay from 24 down to 12V. The dollar for the resistor was much less $$ than buying a 24V relay. I put all the parts in a sealed electrical box used a dose of silicont to plug up the holes, and viola, for about $20, I had a 4-3 wire, 24-12V signal converter.

For the 12V source, I used 12V from the battery, which was equalized by a solar converter.

The only thing odd about the signals was that when the brakes are on, the signals on the trailer flash opposite to the vehicle. Brake off, signals flash the same. No big deal, just a thing to know.

The thing worked awesome for the year I owned the vehcile. Still works, for all I know.

Peter Straub

I think that cardboard box is still around the shop.

[Stone]

Post up the details if you can find it and have the time, Peter.

By the way, caught a couple of glimpses of Tippy R (?) on the Discovery Channel the other week. Cool!

[crushers]

reminder, end of the month the order goes in...

[waaz]

Hello
GROTE makes a DC DC step down converter. Part # 44070. About $ 65.00 cdn. Sealed unit.

[Stone]

Waaz: It doesn't have a logic circuit though...it's just a strict converter, right?

[dieseldog]

Wayne, I'll take two of those things. My 42 and 73 are both 24 volt. I have the one 416 trailer and use any of the four cruisers to tow that thing. I'd really prefer not to double wire the trailer as I'd planned. Count me in for two sets. Neither of my 24 volt vehicles has "engine management". LOL

[crushers]

for those of you that are interested in the group buy, please send me the pertanent info including mailing address to
wayne@crushersrule.com
just to let everyone know as well this is a non-profit endevor.
cheers

[dieseldog]

Email sent. Thanks.

[skinny]

Hey Stone,

Did you have a chance to prove if your circuit design works? Speaking from experience...everything always looks great on paper :-).

I need to get trailer lights going for my rig so I am debating whether to get in on the bulk buy or follow your design.

Thanks,
Todd