Unknown driver?

Tiny
KARMA'S SIDEKICK
  • MEMBER
  • 2004 BUICK RANIER
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 127,000 MILES
My 2004 Buick Rainier cxl 5.3L AWD recently started having issues. I went to start it and it would act like it wanted to start but wouldn't. Then all of the warning lights on my dash came on. My friend checked all of the fuses and they are all ok. He did say he did something to a green printer looking cable that is located in the passenger compartment fuse box located right behind the driver's seat underneath the back seat. When he did whatever he did to that( I'm sorry I don't know what it is called) my car started but all of the warning lights were still lit up on the dash and it said "Unknown driver". Then all of the gauges on the dash stopped working including the odometer. If I turned the car off it would not start back up without messing with that green ribbon under the back seat fuse box. Can you please tell me what that green ribbon is called? What is used for? We have tried everything and checked everything we can think of and have not been able to figure out what's causing the issue. Any new input would greatly be appreciated.
Monday, July 14th, 2025 AT 1:28 PM

7 Replies

Tiny
KARMA'S SIDEKICK
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  • 5 POSTS
This is the green ribbon I was talking about above.
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Monday, July 14th, 2025 AT 1:46 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
The cable is a common failure as it is brittle when it gets old. I don't know if the dealer will have it but they might, I would call the parts department to see if they have one and install it.

The green “printer-looking” cable you're describing is called a flex ribbon cable or flex circuit.

Thanks for the image it helped, let us know how it goes.
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Monday, July 14th, 2025 AT 7:07 PM
Tiny
KARMA'S SIDEKICK
  • MEMBER
  • 5 POSTS
I replaced the BCM ribbon and then my car battery was completely drained dead so I hooked it up to the battery charger. After it was finished charging I started my car and it started but had a rough idle and acted like it was going to die if I didn't keep my foot on the gas pedal. All of the warning lights came on the dash and none of the gauges were working. I don't know what to try next. I'm attaching a photo of the dash.
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Saturday, August 2nd, 2025 AT 3:25 AM
Tiny
KEN L
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It sounds like the BCM is not connected correctly. I would double check the ribbon connections. Lets also do a CAN scan to see if any codes are stored, this video will show you how.

https://youtu.be/u-4syLc-ifQ

Please go over this guide and get back to us.
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Saturday, August 2nd, 2025 AT 9:20 AM
Tiny
KARMA'S SIDEKICK
  • MEMBER
  • 5 POSTS
My car will not give any codes when hooked up to the code reader machine. It says error linking vehicle.I do not know what is causing this to happen because everything is plugged in correctly.
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Friday, August 22nd, 2025 AT 11:28 AM
Tiny
KARMA'S SIDEKICK
  • MEMBER
  • 5 POSTS
Now my gauges work sometimes and sometimes they don't. My windows only work intermittently, my door locks work intermittently (they have never worked with the fob), the service air bag light and security light stay on all the time even though I'm using the original key that came from the dealership when the car was originally first purchased and my back hatch has never locked since I purchased the car. I've also had a problem with my stereo not working, it says it's locked as you can see in the photo I posted. I'm beginning to think I need to just junk this car. I've tried everything I can to fix it( replacing the computer, replacing the BCM ribbon and fuses, etc) and it still is having these issues. My air conditioner started only blowing hot air too. That's really nice when it's 110 degrees and the windows won't roll down. The door locks lock and unlock while driving by their self also, kinda strange.
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Friday, August 22nd, 2025 AT 11:44 AM
Tiny
KEN L
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To me it sounds like the ribbon is not installed correctly, or the BCM itself is out, but it would be nice to see if we could get some codes out of it, here is a video to help get the data port working again.

https://www.youtube.com/watch?v=6Tlg3JmgNSQ

If you want to try the BCM you can get a preprogrammed unit from Flashmasters. Here is the location. I would use electrical contact cleaner in the ribbon connections. Also, if you send BCM in they can test it for you as well. Check out the images (below). Let us know how it goes
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Friday, August 22nd, 2025 AT 1:12 PM

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