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4-wire trailer wiring
Posted: Wed Jul 09, 2008 11:29 am
by Bob Beamesderfer
I'm sure the answer to this is simple, but how do 4 wires cover ground, left turn, right turn, tail and brake lights? The trailer end is a 4-flat connector, with 5 wires coming out of it. The car end is a 4-flat with 4 wires. ¿Que es?

Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 11:33 am
by Aaron Goldsmith
Well... Right Light, Left Light, Driving lights and Ground.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 11:40 am
by Bob Beamesderfer
It appears the answer is the trailer has no brake lights; at least they're not mentioned in the assembly instructions. Harbor Freight at its finest. Guess if I want brake lights I'll have to add them.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 12:17 pm
by Marshall Grice
why would you need a seperate brake light wire? the turn signals and brake lights both operate the high wattage filament in the bulb.
http://www.accessconnect.com/trailer_wiring_diagram.htm" onclick="window.open(this.href);return false;
as Aaron said, you have a left brake/turn, right brake/turn, tail lights (the one with two wires coming from it on the trailer side), and a ground.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 12:39 pm
by Reijo Silvennoinen
4-wires would also cover brakes......which I have had for years.
In fact, I would think a trailer without brake lights would be illegal anywhere.
Reijo
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 3:04 pm
by Bob Beamesderfer
Marshall Grice wrote:why would you need a seperate brake light wire? the turn signals and brake lights both operate the high wattage filament in the bulb.
http://www.accessconnect.com/trailer_wiring_diagram.htm" onclick="window.open(this.href);return false;
as Aaron said, you have a left brake/turn, right brake/turn, tail lights (the one with two wires coming from it on the trailer side), and a ground.
ON the trailer. The Miata has separate turn signals with single filament bulbs behind amber lenses. The dual filament lamps behind red lenses handle brake lights and tail lights on the Miata. I connected the car side per the instructions and the trailer doesn't seem to have any brake lights.
Obvious solution is to run a jumper from the Miata brake light circuit to the left and right wires for the trailer.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 3:18 pm
by Christine Grice
Looks like for the miatas since the turn signals and brake lights are seperate you need to buy a converter kit.
http://www.mainstreet-data.com/trailer/index.htm" onclick="window.open(this.href);return false;
http://www.miata.net/garage/trailerlights.html" onclick="window.open(this.href);return false;
http://www.msprotege.com/forum/showthre ... =123637266" onclick="window.open(this.href);return false;
http://www.topdownmx5.com/Trailer.htm" onclick="window.open(this.href);return false;
http://www.hitches4less.com/power-taill ... erter.html" onclick="window.open(this.href);return false;
Your trailer has brake lights, the miata on the other hand does not have the proper signals to send to those lights. Hence the need for the wiring converter (the wiring on your trailer is good)
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 4:32 pm
by Bob Beamesderfer
Thanks, Christine.
Aaron and Marshall, do you guys not drive foreign cars with separate turn signals and brake lights?
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 4:47 pm
by Marshall Grice
Bob Beamesderfer wrote:Thanks, Christine.
Aaron and Marshall, do you guys not drive foreign cars with separate turn signals and brake lights?
yeah, I just don't waste time putting trailer hitches on them. }:)
besides it's nothing a couple diodes couldn't fix. maybe a transitor or two thrown in for fun. well...and then some resistors. my point is if you would have asked how to wire up a car with seperate brake and turn signals to a trailer with combined brake/turn you would have gotten different answers rather then asking how the 4 wires could do brake and turn.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 5:29 pm
by Jason Isley BS RX8
Marshall Grice wrote:
yeah, I just don't waste time putting trailer hitches on them. }:)
besides it's nothing a couple diodes couldn't fix. maybe a transitor or two thrown in for fun. well...and then some resistors. my point is if you would have asked how to wire up a car with seperate brake and turn signals to a trailer with combined brake/turn you would have gotten different answers rather then asking how the 4 wires could do brake and turn.
Sounds like typical double talk from an engine with an answer but no question.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 8:01 pm
by Bob Beamesderfer
Jason Isley BS RX8 wrote:Marshall Grice wrote:
yeah, I just don't waste time putting trailer hitches on them. }:)
besides it's nothing a couple diodes couldn't fix. maybe a transitor or two thrown in for fun. well...and then some resistors. my point is if you would have asked how to wire up a car with seperate brake and turn signals to a trailer with combined brake/turn you would have gotten different answers rather then asking how the 4 wires could do brake and turn.
Sounds like typical double talk from an engine with an answer but no question.
My sentiments exactly.
Marshall, I realize my question wasn't quite as specific as you required. Christine gets a Starbucks of her choice delivered Saturday A.M. at the SD Div. Aaron gets a rock.
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 8:34 pm
by Will Kalman
Jason Isley BS RX8 wrote:Sounds like typical double talk from an engine with an answer but no question.
OK, I've got your back here, Marshall....
-----------------
A man is flying in a hot air balloon and realizes he is lost. He reduces height and spots a man down below. He lowers the balloon further and shouts: "Excuse me, can you help me? I promised my friend I would meet him half an hour ago, but I don't know where I am."
The man below says: "Yes. You are in a hot air balloon, hovering approximately 30 feet above this field. You are between 40 and 42 degrees N. latitude, and between 58 and 60 degrees W. longitude."
"You must be an engineer," says the balloonist.
"I am," replies the man. "How did you know?"
"Well," says the balloonist, "everything you have told me is technically correct, but I have no idea what to make of your information, and the fact is I am still lost.
"The man below says, "You must be a manager."
"I am," replies the balloonist, "but how did you know?"
"Well," says the man, "you don't know where you are, or where you are going. You have made a promise which you have no idea how to keep, and you expect me to solve your problem. The fact is you are in the exact same position you were in before we met, but now it is somehow my fault."
Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 8:51 pm
by Bob Beamesderfer
I'm not a manager and have no desire to be one.

Re: 4-wire trailer wiring
Posted: Wed Jul 09, 2008 9:40 pm
by Marshall Grice
Re: 4-wire trailer wiring
Posted: Thu Jul 10, 2008 7:16 am
by Christine Grice
White Mocha, Non-Fat, No Whip

Re: 4-wire trailer wiring
Posted: Thu Jul 10, 2008 8:44 am
by Kevin Price
Bob Beamesderfer wrote:I'm sure the answer to this is simple, but how do 4 wires cover ground, left turn, right turn, tail and brake lights? The trailer end is a 4-flat connector, with 5 wires coming out of it. The car end is a 4-flat with 4 wires. ¿Que es?

Might ground connect through the trailer ball- no wires? (It is HF, after all. . .)
Re: 4-wire trailer wiring
Posted: Thu Jul 10, 2008 9:00 am
by Reijo Silvennoinen
Oh, and Christine is an engineer. :gpower:
Reijo
Re: 4-wire trailer wiring
Posted: Thu Jul 10, 2008 9:10 am
by Aaron Goldsmith
Bob Beamesderfer wrote:
My sentiments exactly.
Marshall, I realize my question wasn't quite as specific as you required. Christine gets a Starbucks of her choice delivered Saturday A.M. at the SD Div. Aaron gets a rock.
haha, oh yeah? Well:

Re: 4-wire trailer wiring
Posted: Thu Jul 10, 2008 9:54 am
by Jason Isley BS RX8
Kevin Price wrote:
Might ground connect through the trailer ball- no wires? (It is HF, after all. . .)
Only if you like the trailer lights to blink every time you hit a bump.

I am sure Marshall can offer up some overly detailed insight into the conductive properties of a chrome hitch ball VS a multi-strand copper ground wire.

Re: 4-wire trailer wiring
Posted: Thu Jul 10, 2008 10:53 am
by Marshall Grice
overly detailed? nah.
the grease would kill the conductivity. the end. heheh