Tail light wiring dilemma.

This is for a motorcycle, but the logic is the same on a car.

Once upon a time I had a SAAB 900 which had six filaments across the back. Two each running lights, brake lights and turnsignals. I towed a small sailboat and needed a flat four connector. NAPA sold me this thing about the size of a pack of cigarettes for $16 that made everything alright.

I called NAPA yesterday, yep, got plenty in stock. I picked one up on the way home, installed it last night, NFG. I've got running lights, turn signals and brake lights, but when I hit the brakes with the turn signals on, everybody lights up and doesn't blink.

Let me qualify this by saying electricity and I have never really gotten along, but I did wire it up according to the included instructions. They sold me NAPA part # 755-1539. Any suggestions, ideas etc. greatly appreciated. This is the last hurdle before hitting the road, it already has plates and insurance.

Dan

Is it possible your "pack of cigarettes" is not equipped to handle amber turn signals?

If you had taillights like this...

On these when you have blinker and brake at the same time I think the brake function over rides the blinker function meaning that the bulb just shows brake.

since trailers dont usually have a back up light, and turn signals require 1 wire per side to function, your four wire system should have

a ground a brake light lead, a left marker light lead and a right marker light lead.

keeping these working assumes that the markers are also the blinkers and the brake light bulbs are independent units. is all of this true for your application? if you are trying to operate brake, marker, and turn functions with single bulb on each side then you are correct, the brake light signal will override the turn signal.

Thanks, but it doesn't. I require just what you guys describe and was told the part I bought would get me there. It doesn't. I spoke with the manager of NAPA (I used to work there) and he said, yep that's it.

A magical black box with five wired going in, four wires coming out.

I'm only stupid a little bit, at least I can follow instructions. WTF?

914Driver wrote: This is for a motorcycle, but the logic is the same on a car. ... Dan

What are you trying to do?

Take 6 leads on your motorcyle to 4 leads ... on a trailer? Also on the motorcycle?

That system appears to be designed to take inputs for an "independent system" and make it work on a "common bulb" trailer...

• • You can tell if your tow vehicle (car, truck or SUV) has a common tail light / turn signal system by looking at the taillights (you may have to remove the plastic lens). If the brake light and turn signal are inside a single light bulb it is a COMMON bulb system. If there are separate bulbs for the brake light and the turn signal then it IS an independent bulb system and you can not use this kit

I have a Goldwing that I took all the GW stuff off. Now it has two bullet lights out back with two filaments. Stock Goldwings had three filaments.

If what you say is true, what can I do?

Edit: It looks like I'm going to live with it, just be careful at corners. The brake light overrides the turn signals so I have to ensure to ease off the brake so those around me know what I'm about to do.

Dan

davidjs wrote:

914Driver wrote: This is for a motorcycle, but the logic is the same on a car. ... Dan

What are you trying to do? Take 6 leads on your motorcyle to 4 leads ... on a trailer? Also on the motorcycle? That system appears to be designed to take inputs for an "independent system" and make it work on a "common bulb" trailer... * - You can tell if your tow vehicle (car, truck or SUV) has a common tail light / turn signal system by looking at the taillights (you may have to remove the plastic lens). If the brake light and turn signal are inside a single light bulb it is a COMMON bulb system. If there are separate bulbs for the brake light and the turn signal then it IS an independent bulb system and you can not use this kit

This appears to me to be the problem. Sounds like when you combined wires from 6 to 5 to 4 you combined to brake circuit to the turn signal. They should be independent. Track down each wire seperately on the tow vehicle (bike), they should all use a common ground. A test bulb or multimeter will work. One brake wire going to both trailer lights, seperate turn signal wires for left & right and one running light wire going to both trailer lights plus one common ground. Might get away with using the chassis as ground and not having a ground wire in the plug but need good grounds for that. I assume by two bullit lights you mean one on each side with one 2-filiment bulb in each. If that is the case, not much you can do without adding another bulb or using a 3 filiment bulb and fixture.

I got past the NYS Inspection, the inspector walked around and I flicked buttons. He did not notice that the turn signals were not on at the same time as the brake lights. I got a sticker, took it for a 20 mile blast.

Holy scramble my feedback!!! I could feel the old gas burning off and the 93 kicking in, cleaning things out and yowzah what a piece. It's heavy and doesn't bob & weave like a crotch rocket, but it doesn't recognize tar strips on the road.

I'll be perusing Dennis Kirk for some LED blinks.

Thanx for the help guys, and your patience.

Dan

Oh yeah, pictures coming.....

So you can save a few bucks in the future, all those boxes usually are is a couple of relays hooked up between the turn signal and the brake light.

Take your regular old 12V relay, the square one with the 2 wires for the coil and either 2 or three for the power supply and load. Make sure you get one without the field collapsing diode, should be most of the cheap ones, and they should have a diagram on the side telling you if they have one. Hook the two wires for the coil one to your brake light and the other to the turn signal supply. (Which is maybe where you are having troubles with you box, maybe you hooked up to the wrong side of the turn signal bulb?) Power for the brake light will go to the brake light, through the relay coil, and ground through the turn signal bulb. The resistance of the coil is such that as long as you have bulbs and not LEDs (if you have LED lights and/or the LED flasher your box won't work either) the relay will energize but the signal light won't get enough current to light up.

Turn signal acts the same way, except that it grounds through the brake light. When both are on the relay will have 12V on both sides and won't pick up, so the turn signal on the trailer will flash opposite the turn signal on the car (or bike) when the brakes and signals are on. Supply power to your relay from the fuse box and send it's output to the trailer.