Pre Collision Assist Not Available - BCM Connector 3

[JohnnyX]

I am getting an intermittent 'Pre Collision Assist Not Available' error. When it happens, my brake lights stay on. It is a 24 BL with SAS/LUX. Under 2000 miles. Took it in for service. They reseated connector 3 on the BCM, and problem went away. But it returns. Reseating connector myself solves issue temporarily. Seems a big bump or slamming the tailgate will trigger the issue. Wondering if it is intermittent connector issue or BCM issue. Obviously, I'll take it back into dealer. Anyone else have this? Anyone have a detailed pinout of BCM connector 3?

It is a terrible failure mode. Brake light stays on, even with ignition off. Left this way, the battery drains.

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[Ducati1098]

I’m not sure what they mean by “connector 3”. That isn’t any type of lingo that Ford uses.
Also the BCM is nowhere near the tailgate, so I have a hard time seeing that have much to do with it.

Here are the connector numbers for the BCM. It’s under the dash near the LF kick panel.

 

[BroncoByte]

I am getting an intermittent 'Pre Collision Assist Not Available' error. When it happens, my brake lights stay on. It is a 24 BL with SAS/LUX. Under 2000 miles. Took it in for service. They reseated connector 3 on the BCM, and problem went away. But it returns. Reseating connector myself solves issue temporarily. Seems a big bump or slamming the tailgate will trigger the issue. Wondering if it is intermittent connector issue or BCM issue. Obviously, I'll take it back into dealer. Anyone else have this? Anyone have a detailed pinout of BCM connector 3?

It is a terrible failure mode. Brake light stays on, even with ignition off. Left this way, the battery drains.

@JohnnyX Where is that connector you're reseating located on the vehicle? Is it the one that @Ducati1098 posted the schematics of?

I'm trying to check if this problem is something I could try to fix myself before dropping it off at the dealer.

Thanks!

 

[JohnnyX]

@BroncoByte The BCM (Body Control Module) is behind the dash in front of the driver's left knee. Read my descriptions of the issue very carefully. My problem was mostly intermittent. Make sure the described problem matches yours exactly. I ended up downloading all of the vehicle electrical schematics and determined that it had to be a problem with the Body Control Module or connector. I was also talking with Ford employees directly. But once you mention the words "Brake Issue" (or "Fire"), they are no longer able to continue the conversation for legal reasons. But they did not disagree with my diagnosis. My dealer is great and they let me work directly with the experts in their garage (I went into the garage to discuss with the mechanic). Replacing the BCM is a pain, but easier than replacing the harness. So we decided to do that. It solved the problem. I'm guessing cold solder connection on one of the BCM pins. This would explain why I was sometimes able to reset the condition by removing and reseating "connector 3" -- it passes a key brake signal wire. If you are sure you have the same issue, I can see if I have a picture. There are 3 or 4 connectors on the BCM.

 

[JohnnyX]

@BroncoByte To get access to the BCM, you'll need to drop the IP access panel under the steering wheel. It's not hard, but in case you are wondering.

 

[Ducati1098]

If you are sure you have the same issue, I can see if I have a picture. There are 3 or 4 connectors on the BCM.

There are 8 connectors, but here’s a picture so you can show him which one:

 

[BroncoByte]

Thanks so much @JohnnyX and @Ducati1098 .

The issue is intermittent for me as well. It started after a heavy rain and shows up every now and then when I turn on the car.

I also saw mentioned that it could be a wiring harness in the rear passenger wheel well, so I'm going to look around for any obvious signs there as well. I just recently had to replace the wiring harness for the Cross Traffic Alert module as the wire was exposed and had become damaged over time. That wire was also near the rear passenger wheel well, so I wouldn't be shocked if another wire in the same area had suffered the same damage.

 

[JohnnyX]

Sounds like different issue. Does brake light stay on with ignition off. That was my issue. It also disabled the cruise control.

 

[mwdsonny]

I’m not sure what they mean by “connector 3”. That isn’t any type of lingo that Ford uses.
Also the BCM is nowhere near the tailgate, so I have a hard time seeing that have much to do with it.

Here are the connector numbers for the BCM. It’s under the dash near the LF kick panel.

Where can i find such detailed drawings. I want to add all the wiring harnesses to use factory foglights and i think this could help alot.

 

[Ducati1098]

Where can i find such detailed drawings. I want to add all the wiring harnesses to use factory foglights and i think this could help alot.

You can purchase access to the factory wiring diagrams from Motorcraft.

https://www.motorcraftservice.com/Purchase/ViewProduct

 

[mwdsonny]

You can purchase access to the factory wiring diagrams from Motorcraft.

https://www.motorcraftservice.com/Purchase/ViewProduct

Am I smoking Crack or does that say $3k for 1 year?

 

[Ducati1098]

Am I smoking Crack or does that say $3k for 1 year?

Yeah it’s not cheap. Probably because it also comes with access to a bunch of other stuff.

I have no idea where to get this stuff anywhere else for cheaper or for free, I’ve never looked around.

 

[JohnnyX]

Get a 72 hour subscription and download what you need…. ~$25.

 

[mwdsonny]

Get a 72 hour subscription and download what you need…. ~$25.

I didnt know i could download. figured it was all online only. and not sure what all I would need to make sure I download it all. Is there line a 2021+ bronco folder for lack of a better term that i can just grab, or is it individual books ill have to search for and download? I downloaded the service manual on here but dont think its what ducati was showing pictures of all i could find was ladder diagrams.

 

[JohnnyX]

Not sure. I found what I needed. I may have "print to PDF" (vs. download). I was looking for wiring diagrams/schematics for a 2024 Badlands and got them... I seem to recall there were cable routing diagrams too. You might need to drop $25 and poke around a bit. Sorry, I don't remember how it was organized. It was a while ago.

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