LED issues upon issues upon issues

[Harleyq]

Where to start...came up with the seemingly brilliant idea of changing front
turn signals and back brake/taillights over to LEDs as they are considerably brighter. However, brighter they may be but getting everything to work at the same time has turned into an excerise of futility. First try changed all the bulbs out hit the turn signal and both front came on a t same time. After scratching my head for a moment, or two, I realizes I needed resistors. To the parts store I go, got said resistors, installed and....nothing. was informed I needed another turn signal switch relay so ordered one. Recieved and installed...still nothing. During all this other issues have arised along the way. R rear parking light doesn't work, while left side the brake light stays on. Went back to original light bulbs all around. Front turn signals work as well as R rear, L is still constant brake light so really don't know if signal is working. So far with money spent on bulbs, and various accessories, I've got more problems than when I started. Money well spent right?! I have resistors in line on front but not rear as they were working with led originally. Do I need resistors in line in rear as well? And what else am I missing?? A far wiser master of wire has assisted me in non ked issues, but I'm lost on what I need to do to make these LEDs shine so bright. Any help, advice, sarcastic humor, would be appreciated. I figure I'm too far in to stop now and might as well do whatever I need too, to make them work. Thank you in advance...

[FetchMeAPepsi]

I'm pretty sure you have to switch to an electronic flasher to get LEDs to work. I had to do that on my non GMC old vehicle. Worked great, cost 12 bucks. Also, LEDs only work one way. You can't have the current running the opposite direction like you can with a standard bulb.
If the bulb doesnt work, turn it around. It might work that way.
I have no idea how you got one brake light to stay on forever. That's probably just magic.

[James]

Originally Posted by Harleyq

First try changed all the bulbs out hit the turn signal and both front came on a the same time. After scratching my head for a moment, or two, I realizes I needed resistors.

Both front turn signal can turn on because they require very litttle current. The way our truck is wired, power from one turn signal light is feed thru the turn signal indicator light (from the front lights only) to the oppsite light. Adding a load resistor parallel to each bulbs will prevent this. Also without the resistors the turn signal indicator may (very dim) or may not light up. Resistors are also needed if using the OEM style flasher. The OEM flasher has a bi-metalic spring that heat up causing it to break the circuit. Like FetchMeAPepsi says, using an electronic flasher help. If using an electronic flasher you would only need the resistors on the front lights and not required for the back lights. And yes, they won't work if plug in wrong, polarity matter. Also do not use a LED turn signal indicator bulb, because of polarity it would only flash in one direction and not the other.

Truck wiring can be modifiy to do away with the resistors, but it would require to know where to modifiy and the experence in wiring to do it right.

Originally Posted by Harleyq

During all this other issues have arised along the way. R rear parking light doesn't work, while left side the brake light stays on.

This sound like a turn signal switch gone bad. This is where the magic happen, it cancel the brake light and turn on the turn signal when selecting a turn.

[Harleyq]

Thanks for the advice, just what I needed was more magical mystery stuff going on but man have I got it...with headlights off I have turn signals all around, hallelujah! However, no brake lights. Now with headlights on I have front turn signals and pass side R turn signals. Driver side brake light still shining full time w/headlights. The wall next to my door to my shop has worn spot from banging my head, I love my truck, but we've got to get to an understanding about this lighting situation. Also, as if this isn't enough, I have to hold turn signal switch up or down to get them to work. I'm assuming I have a replacement in the near future....

[James]

Originally Posted by Harleyq

Now with headlights on I have front turn signals and pass side R turn signals. Driver side brake light still shining full time w/headlights. Also, as if this isn't enough, I have to hold turn signal switch up or down to get them to work. I'm assuming I have a replacement in the near future....

I would check the ground on the left (driver side) rear tail/brake light. It could be a bad connection where it attached to the body, corroded connection inside the bulb socket, or a damage wire. This would allow the left brake to come on a little less than full bright because it is getting its ground through the tail/brake light circuit.

Yes you will need to replace the turn signal switch.

[Harleyq]

Thanks James, just got home so will check that first. Going through previous threads, seems the orange wire is carrying power to the black wire which I have power all the way around there at the fuse box, so yea I'm leaning towards bad ground, connection, wire, holding tongue to left when needs to be right. Well here's to hoping for something simple....