Drivers Side Tail Light Problems
Senior Member
Joined: Apr 2023
Posts: 473
Likes: 135
From: TX
I tracked these connectors down a couple of days ago in case it should come up. Got them from Spiky's attachment above.
So starting at C2280D Pin 12 your gy/bn wire goes to C215 which is at the BCM, upper right corner. Then it travels to C134. C134 is on the driver's side either right behind or below the coolant tank or close to that. Then the wire goes to the back between the spare and the bumper close to the center line. It then goes and splits to C4112 and C4113 the stop/turn lamps. From the drawing Spiky supplied earlier there is no relay in this circuit.
So starting at C2280D Pin 12 your gy/bn wire goes to C215 which is at the BCM, upper right corner. Then it travels to C134. C134 is on the driver's side either right behind or below the coolant tank or close to that. Then the wire goes to the back between the spare and the bumper close to the center line. It then goes and splits to C4112 and C4113 the stop/turn lamps. From the drawing Spiky supplied earlier there is no relay in this circuit.
Senior Member
Joined: Oct 2016
Posts: 1,682
Likes: 565
From: Connecticut
I believe the BCM is the control for the light and the relay is internal to it.
The trailer relay is added to grab power from the fuse box and I believe it is then controlled by the BCM.
You have to confirm your getting power from the BCM at pin 12.
Most likely not, which means you need to check it with Forscan.
The trailer relay is added to grab power from the fuse box and I believe it is then controlled by the BCM.
You have to confirm your getting power from the BCM at pin 12.
Most likely not, which means you need to check it with Forscan.
Junior Member
Joined: Aug 2025
Posts: 2
Likes: 1
From: Florida
I had the same exact problem,(left rear brake light and turn signal) had to replace my BCM. That solved the problem. Yes, I checked everything before replacing it.
Bought a used one, then had it programed.
Bought a used one, then had it programed.
Thread Starter
Member
Joined: May 2025
Posts: 39
Likes: 1
Forscan is what I would do next personally.
So, I'm posting the explanation for the stop lamps and the BCM type of codes you might get.
If you have Forscan, I would check the BCM for a "U" code or any codes really.
The BCM can shut down a circuit if it detects a short. Sometimes you have to go into the BCM with Forscan or have the dealer reset the BCM and circuit after the repair.
Or
I'm posting a picture of the connector at the BCM and if you are inclined, I would take my meter and put one probe on the back side of pin 12 gy-bn wire on connector C2280D and the other end on a good ground.
Apply the brake pedal and see if you are getting 12 volts out of the BCM.
Let us know what you find.
So, I'm posting the explanation for the stop lamps and the BCM type of codes you might get.
If you have Forscan, I would check the BCM for a "U" code or any codes really.
The BCM can shut down a circuit if it detects a short. Sometimes you have to go into the BCM with Forscan or have the dealer reset the BCM and circuit after the repair.
Or
I'm posting a picture of the connector at the BCM and if you are inclined, I would take my meter and put one probe on the back side of pin 12 gy-bn wire on connector C2280D and the other end on a good ground.
Apply the brake pedal and see if you are getting 12 volts out of the BCM.
Let us know what you find.
