When applying the brakes turn signal lights blink

Hi,

Is that specific to one side? When the flashers double time, that is an indication there is a burned-out bulb. Check to see if the bulb is bad first.

Next, let me know if this is a 2500, 3500, and so on. I need to look through the wiring schematics and there are differences.

Let me know.

Joe

Wow, the first pic is interesting. That bulb was arcing for power. That's why the connector is black.

Since it works when the headlamps are off, I suspect we have a ground issue. A weak ground can act this way when loaded.

I attached the entire wiring schematic for the exterior lighting. It was three pages long, but I had to cut each pic in half to make it readable. I did overlap them so you can follow from one to the next.

Now, there is a junction block for the grounds related to all taillights. See pic 4. Note that all of the ground wires are black in color. Try running a jumper wire from the right-side light sockets to a known good ground to see if that makes a difference.

Also, take a test lamp and see if (with the headlamps on) there is power to the socket for the signal. Make sure the test lamp has a good ground also. That way, the light itself will provide a ground path.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below.

Run a new ground jumper wire to the signal and see if it works. The present wire itself could be the issue if there is ground at the junction plate, go to the light socket, and check the black wire. If there is no ground, the wire itself is the problem. There could be damage under the insulation that fails when loaded. Make sure you check the wire itself and then the socket. That way, if there is a ground at the wire and not the socket, we'll know the socket is bad. If there is no ground at the black wire, then it's likely the wire itself. You could check the wire for continuity to see how much resistance there is. That could tell us also.

Let me know.

As far as the BCM, there isn't one general test that can be performed to test the "BCM". There are individual tests to check circuits related to the BCM.

Since the issues have changed, are you sure there are no bent or damaged pins on the BCM or the connector? I don't feel the BCM would change issues unless there was a wiring or connection issue.

Let me know.

Joe

Hi,

Everything looks okay. Make sure there are no cracked solder joints. As far as the connector plug color, they don't indicate that in the schematics. If I had to determine which one, I would look through the pinout and identify which wire colors are relevant for the area of interest.

I attached the pinouts below. The BCM pinouts were three pages long. I had to cut them in half so you could read them. They are overlapped.

Let me know if this helps.

Take care,

Joe

See pics below.

Hi,

Did you run a new ground to the affected lights?

Let me know.

Joe

Hi,

Thanks for the update. I'm glad to know you found the issue. Wiring issues can be a nightmare and certainly, a ground can be the cause.

Regardless, take care of yourself, and feel free to come back anytime in the future.

Joe