Turn Signal - Brake Light Blinking Issue

As luck would have it, now that I'm nearing the end of the build I'm running into more electrical gremlins. I know.. I know Just Expect Electrical Problems.

My initial intent was to do a full LED exterior install along with the new High Beam headlights. This went reasonably well until I got into the signaling bulbs which were having none of it. I've swapped back and forth between the stock and digital flasher with mixed results. I added load resistors which seemed to help the back, but not the fronts.

In my frustration I've tried to just put all factory bulbs back in and save this project for another time. Unfortunately now the issue I seem to be facing is that any time I signal with either driver or passenger side the brake lights also are signaling. In my searching I've not found much information other than it might be grounds.

Any help would be appreciated.

its almost 100% a ground issue at the bulb.

all the grounds are connected together on the light housings. when the ground is lost it will back feed into a circuit to find ground.

like when the headlights lose ground it will back-feed through the high-beam filament and both will glow but will be very dim.


check all the bulb sockets for corrosion and check the connectors to the tail light housings. leds are much more sensitive to missing grounds as it takes almost no power to light them.

I finally got some time to work on this over the weekend. I did see that I had a trailer wiring setup which I believe was part of the problem. I got all the lights to function as intended, and then even got the LED's to work as well.

After several hours of getting to this point they seemed to just stop working on the passenger side. Due to some sheer luck, I went over and moved the passenger front door and everything lit up. Cycling the door open and closed a few times I noticed that the aftermarket door close sensor would kill the functioning of the passenger lights as soon as it was depressed.:flamemad:

I pulled the switch out and had to connect two of the leads, but all seems to be working well now.