bliss

Hey all, i have a 07 JK that i have had a few years. I need help figuring out how the stock turn signal/brake lights work, and where their components are.

Before i got my jeep it was modified where extra lights were added into the rear light enclosure and the power for these extra lights were tapped off the front turn signals. Not sure why this was done, but its what i have to deal with now.

I want to return my jeep to the normal operation where the brake lights flash as blinkers.

Currently my rear brake lights stay constant and overall the blinkers are dim because they have increased loading on the front blinker circuits.

Any ideas on where to look for the brake/blinker light logic components would be appreciated.

HoodJK

Here are the wiring diagrams for the rear left and right tail lights. Note the colors of the wires. Hope this helps.

Rear Left Tail Light:


Rear Right Tail Light:

bliss

unfortunately no.
The resolution makes it hard to read, but what i can see from it its a little too far downstream.
Thank you tho.

HoodJK

That's the whole diagram, including the battery, switch, and light. I couldn't make the resolution any better without using photoshop (too much work).

JK-Ford

This shouldn't be that big of a deal. Just reconnect anything that was previously disconnected. And disconnect anything added in. I pretty sure that there is no flasher relay like in older vehicles.

bliss

As far as i have seen there is no flasher relay.

I dont know what was disconnected previously. The brake lights should flash when your blinker is on, and it does not. That makes me think that something was bypassed but i dont know what or where.

The images just have a dotted box labeled electronics, and not what or where those are. I need to get into that dotted theoretical box to fix this.

I appreciate the effort you have already put in. thanks

HoodJK

I zoomed in on the diagrams and tried making it easy to understand, however this board limits the size of the images you can upload and automatically scales them down. That's unimportant right now though. The stock tail light has three lamps in it, one for when your parking brakes are on, one for reverse, and one for turning & braking. What you need to first do is to test whether the tail light get brighter/ another light turns on when you hit the brake pedal. I suspect it won't since the brake/turn signal light get its signal from the same place.

If it does light up when you hit your brakes but not when your blinker is on, then the wiring going to the light is good but the control is not getting a signal from your turn signal handle.

If it does not light up when you hit the brakes, then the tail light isn't getting the signal from the control (most likely because of bad wiring) or the tail light doesn't have three lights in it.

I can help you further once you test that.

Rear Left Tail Light (Includes the trailer wiring)


Rear Right Tail Light (Easier to read)

bliss

No, my model JK only has two lights in the rear lights. One which acts as a break/marker/signal light, and one for reverse.
Pretty sure that is a common thing in the JK models

HoodJK

You're right, there are only two bulbs, but the top bulb has two filaments in it. The smaller outer filament is for your regular running lights, and the thicker inner filament is for your brake and signal light. I'm curious to know if that thicker filament lights up if you press the brakes. If so, then your lights are fine, but it's not getting the signal from your turn switch.

Upper Bulb


Running Light


Brake/Signal Light

bliss

I understand how the two filaments work, and you have it right.

The heavier filament lights when brakes are applied.
The normal operation has the brake light flash if the blinker is applied and is on constant when the brakes are applied. If both (brakes and blinker) are applied the side with the blinker applied will flash and the other side brake light will remain on constant.
The electronics to process this must be in the car somewhere, i just dont know where.
I just really dont want to trace the wire to the brake light throughout the jeep, and i was wondering if anybody knew where that logic(electronic) was.

My guess is that somewhere the turn signal and the brake signal meet and the turn signal has higher priority and the brake lower. It would be simple to do with an exclusive OR gate.