Hi, I hope I am doing this right as I am a newbie here. I have a 2001 Buick Lesabre. One day all of a sudden both back windows quit working. Also the power locks in the rear quit working when I put the car in and out of gear. Also the rear locks refuse to work from the key fob.When the car is unlocked the interior light also fail to work when the rear doors are opened. I have read about the Bonnevilles problem with moisture under the drivers seat. Other than normal snow being brought in on my feet, (I live in MInnesota) I dont thinkn that moisture is a problem. Does anybody have any ideas? Drivers door module? rear integration module? Thanks.

Do the locks work at all? FOB, drivers control, rear door control? If nothing, then I woudl tend to think it'* the drivers door module.

No power on the rear door locks with anything front ones work with fob or switch.

Start by checking for power to the rear controls. No power there, then move to the drivers door control.

2000 lesabres and newer tend to have numerous issues in the electrical department, as well as... every... other.. department... I'll never own one.

I swapped out the drivers door module today with no luck. I wonder if this is the same problem that Ive read about with corrosion on the serial data line.

Today the front passenger window and lock quit working. Now the drivers door window and lock are all that is working.

It sounds like your DDM is going.
Honestly, I'd take it to a dealer and pay for the diagnostic on it. Their scanners (tech2) can read and see things that we can only guess at without it. Rather than chase down a bunch of "maybe" items, they can tell you what exactly is wrong. Then you can do the legwork replacing the problem items, so you don't pay them for labor.

If you have heated seats that work, try turning on the passenger side heater and see if it works. It sends a signal through to the DDM to turn it on. If it worked before, and now doesn't, then even better bet that your DDM is going.

Its really too bad you can't get a tech2 for under 5g. It really makes it tough to diagnose communication and module problems in cars this complicated.

I swapped out the drivers door module, at that time the back windows and locks didnt work. The module was used but the symptoms were the same.

serial data connection issue very common on 2000 and up GM'*

Not hard to fix either, here is a web link to show you where to find the serial data line that has the problem:

http://www.autotechonwheels.com/2010...itching-it-up/

I live in MN also, and the water from your shoes (from snow) will get down threw and rot this out