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Discussion Starter #1
Hey,

My interior dome light won't go on when i open the doors, but goes on no problem when i switch it manually. I never move the switch, and always had it in the 'auto' position. It can't be the door switch because it stays off when the other doors open (or is the driver door the only one that turns it on? i forget)

I checked the fuse and it isn't that. any ideas?

2006 4 door LS

Thanks
 

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That is a signal from BCM. All doors should turn on the dome light. There are 4 seperate wires, one from each door switch,going to BCM logic circuit which actuates the signal going to dome light center position.
 

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would this also explain why my remote unlock/unlock doesn't work all the time (battery replacement did nothing)?

well i just did a search on the BCM, and didn't know what it was... i found some on ebay used for like 40 to 60 bucks, but the dealer apparently needs to flash it to work with the car. Would i be able to install it, and still be able to drive a day or so until at the dealer? how much will that cost do you think?

also, not sure if it is an indicator that the BCM is toast, but it the fuse 'tabs' are slightly discolored...
 

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Probably not the BCM that's at fault but rather the connections.
Before you buy anything....
1. Disconnect car battery
2. Find BCM. Hiding under fuse plastic cover on passenger side.
3. Pins tend to eventually corrode so you might try to disconnect the two blue connectors and reconnecting just to see if this clears the dome light problem (pin A10 for domelight) I've highlighted the related parts on diagram.
4. Also there is a connector in the trunk that supplies the headliner you might want to disconnect and reconnect just to clean it or eliminate that connector. Be carefull not to break wire going to rear window defrost.

As far as your remote it is probably the contacts in your FOB. There's a thread on this problem on here. My post is #13 http://www.yourcobalt.com/forums/install-guides-diy/25544-how-fix-nonworking-buttons-keyfob.html
 

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10mm nut on battery clamp.
 

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That is a signal from BCM. All doors should turn on the dome light. There are 4 seperate wires, one from each door switch,going to BCM logic circuit which actuates the signal going to dome light center position.
Coby, I'm just waiting for you to share with us that you worked for NASA for 3 decades. Seriously dude, great to have someone with your level of knowledge here!
 

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Didn't know somebody else read these. Just glad to help. I'm a Broadcast Electronic engineer by trade and spent my last 15 years teaching new comers the trade. I've restored a 59 Corvette from scratch as a hobby. I like to fix my own car when I can and help others fix theirs.
 

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Discussion Starter #10
hey,

Thanks for the heads up on the keyfob, worked like a charm! unfortunately the dome light still isn't working. There is no way i'm going to the dealer at the moment, so i'll just have to live with no light. Now, other than the dome light not working, is there any other way to confirm that the problem is the BSM?

Thanks,

Brad (68 Vette owner, hoping someday to restore!)
 

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It's BCM (Body Control Module), and you can check if BCM is puting out a ground at pin 10A gray wire when a door is open. You can also apply a ground to this pin to verify harness and to see if light comes on with connector removed of course. It might even be the switch that went bad.
 

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One good trick I found to check wire conductivity without destroying that insulation is by using a pin or needle which you pierce the middle of the wire. Then you can clip your lead to pin. Once your done just tape it or small dab of silicone if it is an exterior wire. Have fun probing.
 

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HENDRIX7979, I'm really sorry for leading you in error. After researching further it is not the blue connectors it is C3 the pink one. Here is what I found and this time I'm not talking through my hat. A10 gry was right though.
 

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