LED light kit not working right

[Sixpack57]

2006 CC Precedent 48 v (4x12)
I’m installing a LED ultimate light kit. After getting everything installed, and plugged in, ran into the following problems:

When left turn signal activated, the headlight blinks
Left rear taillight stays bright, ie brake on
Right rear taillight not doing much of anything

I was told, by the supplier, that the TS switch was backfeeding, so they sent a whole new kit. Swapped out the harness and switch- same problems.
I’m beginning to think there’s a problem with the factory prewired harness, although that shouldn’t effect the headlight. Checked the ground at the controller- it seems good. Not sure what else to do but rip out factory wiring and buy a bucket harness and start over.

Any suggestions are greatly appreciated!

[Gearhead1956]

I would check the GROUNDS!

LED'S need good grounds more then incandescent bulbs do. If not they will do funny things!

good luck

[Sergio]

It is probably your LED tail light assembly.

The Headlight power is connected to the tail light "marker" lights.

What happens is some of those Tail lights share the "marker" and "turn-signal/brake" leds so if they are not properly designed, providing power to the turn signal will back-feed the "marker" circuit which in turn will turn on a dim headlight.

The solution is to install a diode near each of the tail light in series with the "marker" power wire, usually brown wire.

The diode cathode or end with a stripe will go towards the tail light.

[fresnel151]

I used Sergio's diode solution to resolve a similar back feed problem with a new LED headlight on my 06 Precedent. However, I had to install a single diode in the brown wire of the harness under the dash before it connects to the light kit harness. Couldn't get a diode on each taillight to kill the back feed for some reason.

[Sixpack57]

The taillights May be a problem. My dog chewed the wires from one of the lights that came with the kit. Ordered 2 more from another source. Plug was the same, but the assembly was a little different. Don’t know if it makes a difference, but I do wonder. I’ll try your idea and see what happens. Thanks!