Much less dramatic "Wire Issue"

[Bill DiGuiseppi]

So, got the hitch installed on Mike's Miata for the Harbor Freight trailer and then noted we probably ought to have some trailer wiring . Bought the converter kit for 2 light systems to go to the one light trailer. Brown=brake, green=right turn, yellow=left turn, white=ground, red (of converter)=headlights. But, both lights flash on either turn signal and putting the headlights on messes everything up. Removed trailer ground and scraped off mounting to reveal bare metal. No diff. Hooked a jumper cable from car ground to trailer ground. No diff. (Trailer lights are a 2 wire circuit, not grounded anyway, but that is a common trailer lighting problem.)

Any bright ideas?

[Jeffrey Hugo]

either you spiced into the wrong circuit, or there is a short somewhere. Time to bust out the DMM if you haven't already

[Eric Hahn]

Don't know the specifics of your converter, but in the golden days of trailer wiring...Brown was the running lamps, green and yellow were signal AND Brake. I have a spare converter somewhere...with a diagram on the box. Converter takes the signal from the car with amber turn signals and red brake lights and converts to the old fashon American - same fillament for turn and stop. I think there is something fishy about your instructions. When the book says "connect the black wire to earth" I always slow down and recheck things.

If you need my converter (no charge) I can look for it tonight. I could also check it for wiring help and compare it to yours.

[Matt Leicester]

Originally Posted by Billdig

So, got the hitch installed on Mike's Miata for the Harbor Freight trailer and then noted we probably ought to have some trailer wiring . Bought the converter kit for 2 light systems to go to the one light trailer. Brown=brake, green=right turn, yellow=left turn, white=ground, red (of converter)=headlights. But, both lights flash on either turn signal and putting the headlights on messes everything up. Removed trailer ground and scraped off mounting to reveal bare metal. No diff. Hooked a jumper cable from car ground to trailer ground. No diff. (Trailer lights are a 2 wire circuit, not grounded anyway, but that is a common trailer lighting problem.)

Any bright ideas?

Output wise anyway, brown is running lights, green is right turn and stop, yellow is left turn and stop, white is ground. I suspect your inputs should be the same, and just the red is brake.

Matt Leicester

[Hank Derr]

Bill, have you seen this?

http://www.miata.net/garage/trailerlights.html

[Darren Kidd]

Wires?

you need no stinking wires!

DK

good luck

[Bill DiGuiseppi]

Thanks to all. In addition to following all the advice here, I did 2 things that seemed to make the difference:

1. Ran separate ground wires from the point where the wiring is grounded near the tongue to each of the rear light assemblies.
2. Replaced most of the bulbs with LEDs.

The ground helped some, but it was not until the bulb replacement, because apparently the poor little Miata's relays could not handle doubling the load.

It is not PERFECT because the lights blink out of sync/opposite of the cars lights, but they fundamentally do what they are supposed to do.

[Eric Hahn]

Wonder if you are fighting a non electronic flasher (old school flashers did not like additional load)? You might see if there is an electronic version for the car.....

[Mike Michaelson]

Originally Posted by DTI Eric

Wonder if you are fighting a non electronic flasher (old school flashers did not like additional load)? You might see if there is an electronic version for the car.....

You mean the old clicky relays? What they don't use those anymore?

[Bill DiGuiseppi]

Originally Posted by 47ford

You mean the old clicky relays? What they don't use those anymore?

Well, the car IS from the last century!