I have a 2002 Bonneville ssei. All 4 doors are for all practical purposes dead. Remote will not unlock. Windows, locks, mirrors and lights in ***** do not function using door controls. Key fob does open trunk and interior lights come on when unlock button is pushed. Have power to all fuses and power unlock breaker. Not sure where to look next. I know each door has a separate door control module and fuse for each. Apparently there has to be a common circuit for all four doors to quit at the same time. Does anyone happen to know where this might be. At a serious loss. Thanks to anyone who can help.

The serial data comes into the Driver'* Door Module (DDM) on a purple wire. The data exits for the other doors on a single, white/off white wire. I suspect you have a bad DDM, a broken serial (purple) wire to the DDM, or a broken power wire to the DDM, in that order of probability.

Thanks for the info. I knew there was a common circuit.

Agree with the Geek, except for the fact that power and ground is common to all 4......

But every module has to have power, ground, and serial data...a bad module that is shorted out, can also take down the serial data line(there are two serial data lines, one for all modules in the car, and one that connects all four door modules)...

Access to a Tech II scan tool makes diagnosis infinitely simpler, but most people don't have one...

So diagnosis can be laborious....To have a shot at this, you at least need schematics of each door module to test power, ground, and serial data lines......another thing you can do, is disconnect all four door modules......then reconnect one and see if that door works....if it does, leave connected(if it doesn't work, disconnect it again)....now reconnect another door module...if it works, leave connected...connect another, let'* say that door does not work, and now the other two doors that previously worked, don't work either....this means the last module you connected is bad and taking down the system.....

Did this happen all at once, or did one door fail, and then another?

Yes, by all means. If I was misunderstood that only the DDM had a power feed, I apologize.


This does make me have questions of my own. I have assumed if the secondary bus (for lack of a better term) between the doors becomes shorted to ground, that it will not kill the main serial bus. Is this accurate? While I've had a DDM open, I've never looked to see how it is designed in this area. I've assumed it is totally isolated and not even communicating on the same protocols.






In the event a door module, other than the DDM, loses power or ground, does this also shut down the other modules? I would assume the DDM would at least still function in the scenario.

All doors quit at the same time. Worked then car sat for about three days then did not work.

One other thing. There were no symptoms prior to the failure. One day worked next day didn't.

How are the battery and alternator doing?

Overly simplistic I know, however: I'd try disconnecting the battery for an hour. Reconnect and see what happens.

I see what Cathedral is doing here......by disconnecting both battery cables, and then , jumping them together, for about 10 minutes, this RESETS every module in the vehicle......

But my money is on a bad module or shorted data line....

Thanks at this point I'll try anything