Why would the electric locks in a 1992 Cadillac DeVille randomly lock and unlock themselves?

Answer 1

Chances are your transmission selector switch is out of adjustment and activating your automatic door lock module. See if the car will allow you to start it in Neutral. This only applies of course if it happens while the key is ON. If the problem is a defective trans switch by now its so severe that it should of activated a service soon light. (code 91)

Myself or someone else needs to know exactly when this happens to be of more help. No matter what, you can make it stop by first only unhooking the automatic feature of the electric door locks. It is a square black box that gets thicker on one end, clipped to the passenger side dash area just to the left of the relay panel. You have to lower the insulator panel, or go in through the glove box unit after you remove it. The 5 or so wires will be light duty thinner gauge ones. You will see pink, light blue, light green, white........ The end of this opens up and a small circuit board will unplug out of the plastic box using a small screw driver. This way you can still use your lock switches or remote (if equipped) but the car cant lock doors when you shift from park anymore.

If you do this and the problem still occurs, its just a door lock switch, or a more serious problem. This all applies to a factory lock system. If your cursed with an aftermarket car starter remote system, then GOOD LUCK, HA! I hate the way some installers in these shops wire these to lock car on its own. :)

== == == == My Beretta did that. Turned out the battery was dying. Go have it checked before you're left stranded... in the meantime, yank the fuse to the locks to stop that from happening (as long as the same fuse doesn't affect exterior lights).