Passenger Door Locking

[LizardRunner]

That can also be caused by the skimpy wireing harness in the doors. The wires will break.

[JeepFreak]

I have heard of certain connections in the door locking mechanisms breaking and whenever you hit a large enough bump it will tap the two broken ends together which would cause a sudden signal to jump through the circuit which would cause the doors to lock and unlock. Try starting at the lock itself then trace it back to anywhere that looks crimped or torn or somewhat bent and of course the obvious breaks. If there aren't any, I have also heard that power surges in the battery cables themselves can cause unwanted power being drawn to different parts of the electrical system. If there's no obvious signs of wear on the wiring in the door, I would suggest taking a look at the electrical components in your door such as the actuators since they may be getting a signal from either a faulty wire or a bad ground. If you still can't find anything then I would suggest taking a look at different parts of your car that are electronically controlled such as the spark plugs, fuel injectors, stereo and other various electrical components. If you notice something different about the way they perform then maybe it ties in to what the current problem is. Fuel mileage actually goes a long way for some electrical problems since a mistimed spark plug or fuel injector from a bad lead causes lower than average MPG. So if you notice anything else that's not performing optimally I wouldn't rule it out as being caused by the same issues.

Recap: Start out small (check the locking mechanisms for signs of wear, this includes the locking actuators, wires, and any other electrical components involved). If the problem isn't obvious there, move on to a slightly bigger option that's more broad such as an electrical malfunction caused by a power surge of some kind. If the problem still cannot be remedied and you have no further options to look at and nothing else is wrong electronically in your car, then I would suggest taking it to a mom and pop shop to have them test the wattage being drawn if you don't know how to do so yourself.

Hope this helps!