I just can't get my tail lights to work right!

[Dr. Awsome]

All right so here's the problem. My brother and I are trying to wire some new LED trailer lights into his baja bug. We only want to have to use one set of lights so we are running all the electrical through a trailer adapter so make the system a running, stop/turn. Everything is working fine so we get normal running lights and normal brake lights but we only get blinkers when the brake is on. So no blinker when the brake peddle is not being pushed but there is blinker when the brake pedal in being pushed. We have tried fixing it several different ways. We have tried wiring a resistor to try and trick the flasher into thinking there is a normal bulb back there. We have also thought that some how the current would be flowing back upstream to the brake switch so we unhooked the brake wire from the system and we still have the same problem. We also heard that it might be a ground issue so we grounded the whole rear lights system straight to the battery negative post. We also just for kicks thought that all the current might be going to the front bulbs and not going to the rear due to the path of least resistance. When we pulled the front blinker bulb and we then lost all blinker as well as the brake light. As you can imagine we are pretty frustrated and completely out of ideas so any help would be great!

[movindirt]

I know if the brake and turn use the same wire on the light then you need to run diodes on the connection of both to the main wiring. But if you didn't have those you should make both sides flash when either turn signal is on. Sounds to me like you are not getting 12v to the turn signal circuit unless you close the brake switch. I would check at the input to the turn sig relay. It should show 12v at that point with the signals on.

[Superfab]

Last I knew you have to use a special led flasher when you switch to led lights due to the different current draw. Try NAPA, they might have one. I would think that the front bulbs need to be led also so everything matches ???

[ntsqd]

LED's only need a non-mechanical type flasher. They don't draw enough current to warm up the bi-metal in a mechanical type flasher. Shouldn't need to have LED's in front for everything to work.

I'm thinking Tony is on the right track. You don't have power to the turn signal switch unless the brake lights are on. Have a look at where the turn signal switch gets it's power from.
FWIW I've not had great sucess with those trailer light adapter/converters. Usually it's the turn signals that don't work.

[johnowhite]

Now you know why there are usually three lights in the back. Tail, brake, and turn.
It's so much easier to trouble shoot when you can isolate the cirduit. I'm building a baja pre-runner and wanted to do what you're doing, drew it on a piece of paper, couldn't get it to make sence.

Blinker circuit
Power to your blinker - if you power your front blinkers (non-led) (three terminal) and rear blinkers, you may not need an LED blinker. After your blinker, power your left and right lights.

Brake circuit
power to one brake switch terminal, other terminal to brake lights. (If your brake lights and blinkers are on the same circuit, your front lights may come on with your brakes.)

Tail lights - power from ignition "On" switch or light switch.

John 805 844 4665

[ntsqd]

I've had two of those not so inexpensive 6 to 4 light trailer converters go tango-uniform on me so I decided to see if I could do it with relays. You can, but you need to have battery power available.

I have drawn it on paper and it looks like it will work. I've worked the logic from every angle I can think of, and it appears that it will work. As soon as I'm not working 16+ hour days (this weekend?) I plan to build it and see.