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Possible BCM problem?

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Old Sep 29, 2025 | 01:48 PM
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Default Possible BCM problem?

Hi fellas, new to the forum and a new owner of a 2002 Trans Am WS6. I've only had it a couple of weeks and have had nothing but problems, which I didn't expect for a car with 67,000 miles.
The problem is the radio cuts in and out, the mirrors don't work and the passenger window can't be controlled by the driver door switch. I did a lot of reading, removed the BCM but I didnt see any solder cracks that everyone refers to. Any help will be greatly appreciated, thanks , Tom
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Old Sep 29, 2025 | 04:57 PM
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Check the driver's side door harness where it flexes between the door and the body. Pull back the rubber boot and look for broken wires. This is a super common problem on these cars and causes exactly the issues you're describing.
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Old Sep 30, 2025 | 09:30 AM
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All of these problems are common for a 25 year old car... Mileage has noting to do with electrical terminals/internals corroding, plastic becoming brittle and rubber seals becoming stiff/leaking.

None of this is a BCM issue. As tmarsh518 pointed out, you could have a harness issue but I would take the door panel off and see if the plastic vapor barrier is still there. (It looks like a piece of clear plastic stuck to the door with black goo.) This keeps excess moisture away from things like the door switches. Even with the vapor barrier in place, it won't keep all the moisture/water out.

Originally Posted by tmarsh518
The problem is the radio cuts in and out
This is a common problem with the stock radios from the factory and a common issue is a dirty volume ****. If the volume **** also doesn't work correctly, then take the **** off and spray MAF cleaner down the post, turning the ****. That should clean out the dirt. If this isn't it, please post a separate thread to the Stereo and Electronics section.

Originally Posted by tmarsh518
the mirrors don't work
Cars of this vintage will have the multi-function mirror switch fail. You can test it with an electrical diagram (download for free from Autozone.com). If you remove the switch from the trim, do so VERY carefully as the trim plastic will be brittle and it will be expensive to replace.

Originally Posted by tmarsh518
the passenger window can't be controlled by the driver door switch
If one switch works and the other does not, its usually a bad switch. If you remove the switch from the trim, do so VERY carefully as the trim plastic will be brittle and it will be expensive to replace. Again, you can test this with an electrical tester before making a swap.
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Old Oct 1, 2025 | 09:21 AM
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Thanks for the responses. I did replace the driver's door window switch to no avail. Will report back after further investigation.
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Old Oct 3, 2025 | 04:55 PM
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Originally Posted by tmarsh518
Thanks for the responses. I did replace the driver's door window switch to no avail. Will report back after further investigation.
You need to test the switches. Less common, but check the schematic. The passenger side switch could also be bad. (Power from the driver's side flows through the passenger switch to the motor at all times.)
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Old Oct 9, 2025 | 02:06 PM
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Update: I going to say I have 3 separate problems. I tried the MAF cleaner suggested by wssix99 and that didn't work. I replaced the mirror switch, now the mirrors are working. I replaced the driver's door window switch and the passenger window does not work. The passenger door window switch does work properly. I'm assuming the radio is no good and further testing is needed between the driver door window switch and the passenger door. Thanks for the info, guys. Tom
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Old Oct 9, 2025 | 09:26 PM
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Please create a new thread in the Stereo and Electronics section for your radio problem. We have some folks over there who can help you track down that issue.

The passenger window is a complex circuit. The drivers side switch for the passenger window has connections that flow through the passenger side switch. So, even though the passenger side switch may work the window, the switch contacts that connect the circuit for the driver's side switch can still be bad. You can also try switching the passenger side switch or test it with a simple continuity tester and schematic.
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Old Oct 10, 2025 | 11:11 AM
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BTW - You can download the official GM switch schematics for free from Autozone.com
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Old Oct 10, 2025 | 02:28 PM
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Thanks, brother
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Old Oct 19, 2025 | 02:35 PM
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Originally Posted by wssix99
Please create a new thread in the Stereo and Electronics section for your radio problem. We have some folks over there who can help you track down that issue.

The passenger window is a complex circuit. The drivers side switch for the passenger window has connections that flow through the passenger side switch. So, even though the passenger side switch may work the window, the switch contacts that connect the circuit for the driver's side switch can still be bad. You can also try switching the passenger side switch or test it with a simple continuity tester and schematic.
Needless to say, you were right. Checked switch, NFG. Put in new switch, works like a dream. Thanks again, I never would have suspected that switch because it was working on that side.
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Old Oct 20, 2025 | 08:58 AM
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Super cool. Looking forward to your thread in the Stereo section. We should be able to get that working, also.
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