If you are going to fix this yourself it sounds a lot like either the wiring or switches for the door lock system is at fault. The door lock is just a solenoid (a relay like device except instead of changing electrical contacts it moves a plunger) so it's getting toggled somehow when you don't want it to. So, something is applying power to the solenoid on a random basis. First thing to look at is the switches. There are only two that control all of the locks in the car, and that's the two in the front door pull handles. They are easy to remove. Once removed try putting a DMM (Digital Multi Meter) in resistance mode across the switch and gently push on the switch without actually changing it's on'off state. If the resistance is stable at infinite or zero then the switch is likely good. If it's flaky, and jumping when you touch it (even without actually moving the switch handle) then you likely have a bad switch. You can also try the test listed earlier and just remove one of the switches at a time and see if you can reproduce the problem.
If it's not the switches, you can find the wiring diagram for the car online, or in some of the Chilton manuals. Given that the problem is power being applied randomly, it seems unlikely that something is shorting 12V to that solenoid with a short, but it's possible. Try looking for power at the solenoid (inside the door lock mechanism) when moving the harness. First place to check would be the wires that run between the body and the door, as they take the most abuse.
Honestly I think it's the switches, and it you test them thoroughly you'll find the problem. And more good news, they shouldn't be expensive to replace.