The power door locks on my 2003 Express 3500 lock and unlock by themselves. It happens mostly when driving, but sometimes when I shut the door, I hear the door lock. This is aggravating! Any ideas? Thanks.

 

Sounds like you have a short or a bad switch. Does one of the switchs feel worn out? I would start with the door you shut that causes the doors to lock. Sounds like when driving, if you hit a bump or something it will trigger the short or bad switch to trigger lock/unlock.

Does it just do 1 thing like always unlock or lock? Or is it random with lock or unlock