V1 Captain Dave's City Goblin #336 - 07 SS/SC Donor

[Markm]

C2 has micro 64 terminals. Be careful front probing micro 64 they’re fragile. Back probing would probably be better in this case.

 

[Captain Dave]

C2 has micro 64 terminals. Be careful front probing micro 64 they’re fragile. Back probing would probably be better in this case.

I am going to check this out tomorrow. It looks like on my BCM the brake lights are in the C3 plug. A9 and A12. Does that look correct to you?

 

[Markm]

I thought I added the schematic but I guess I missed it. Those are the output to the lights. C2 has the input

 

[Captain Dave]

Ok so we are still chasing a brake light issue. I have turn signals, taillights, and backup lights. I have power at the third brake light. Testing with the ignition switched on. So far I have tested that I have power going to the stop light switch and power leaving the switch when the brake is pressed. I have power at the BCM C2-54 pin (stop lamp SW sign) when the brake is pressed. I do not have power at the C3 A9 or A12 (Left and right rear supply voltage). If I run a jumper from C2-54 to C3-A9 or A12 the brake light illuminates regardless if the ignition is switched on or not. I have replaced the BCM with the same results. The new BCM did get rid of my alarm issue when the ignition is turned so that was an added bonus. I have also conducted a pin drag test and all connections seem to have the same resistance.

What else should I try? What are the chances that two different BCMs could have the same issue with the brake lights?

 

[Gtstorey]

Ok so we are still chasing a brake light issue. I have turn signals, taillights, and backup lights. I have power at the third brake light. Testing with the ignition switched on. So far I have tested that I have power going to the stop light switch and power leaving the switch when the brake is pressed. I have power at the BCM C2-54 pin (stop lamp SW sign) when the brake is pressed. I do not have power at the C3 A9 or A12 (Left and right rear supply voltage). If I run a jumper from C2-54 to C3-A9 or A12 the brake light illuminates regardless if the ignition is switched on or not. I have replaced the BCM with the same results. The new BCM did get rid of my alarm issue when the ignition is turned so that was an added bonus. I have also conducted a pin drag test and all connections seem to have the same resistance.

What else should I try? What are the chances that two different BCMs could have the same issue with the brake lights?

Hard to say without you supplying a full diagram.

 

[Robinjo]

I have BCM C2 pin 54 (light blue) as 3rd brake light. You'll have to look at the full schematic to see where BCM A9 (Tail Light Left) and BCM A12 (Tail Light Right) get their power from.

I'm not sure if the two tail lights get power distributed from the 3rd brake light or not.

 

[Captain Dave]

Here is a diagram of the BCM.

 

[Robinjo]

Silly question here. Are you sure you have the rear lights hooked up right? Just strange that both BCM's gave the same result. Are you using the DF tail light kit or some other lights? Here is my schematic that worked.

 

[Captain Dave]

Silly question here. Are you sure you have the rear lights hooked up right? Just strange that both BCM's gave the same result. Are you using the DF tail light kit or some other lights? Here is my schematic that worked.

View attachment 54437

Unless there is an issue in the wiring harness somewhere, the lights are hooked up correctly. I have taillights, turn signals, and backup lights. The brake lights and turn signals use the same wire for power. For now I am going to use the third brake light wire and split it off to the two regular brakes lights and run an external light for the turn signals. At least that makes all of the lights work and gets me on the road.