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1999 Subaru Forester L Door unlock and lock durring driving

I recently recieved a 1999 Subaru Forester L from my parents to allow me to get transpertation to and from an internship this summer. The car has only 40k miles on it and has spent many of the past years parked.

When traveling in the car the doors will seemingly random toggle the locks turn on the dome light and the guage lights turn on then off.

If the doors are locked the doors will unlock then lock and then unlock and lock. If unlocked it will lock then unlock then lock. So it is not consistent the amount of locks/unlocks being done.

We have removed the batteries from both keyless remotes and the problem still persists. It will not happen if the key is not in the ignition. It has only happened once in accessory mode and happens multiple times per trip when the engine is engaged.

I thought it was an issue with an autolock feature when driving past a certian speed but I could find no reference in the manual to the car having such a feature.

My Dad believes he can determine the issue if he has access to the wiring diagram but I have been unable to locate one for a 1999 Forester.

If anyone knows the issue or where I can locate the wiring diagram in question please let me know. Thanks for any help with the mystery of the locking doors.

I think your trouble may be due to dirty switch contacts on the lock switch that is used for the door key lock. It is located inside the door panel on the door lock. If you want to prove it you could disconnect it and see what happens. There may be one in the passenger door also and if so I would suspect the driver side first for the trouble.
If that isn’t causing the trouble then I would check the Keyless Entry Control module that is used for the keyfob remotes and the door switches. The Integrated Control module drives the lock motors.

Here is a link you can refer to if you want to pay for a download of the service information.

Many thanks for your advice! We will try your suggestions! We will also use the link you provided to get some manuals. Thanks so much for taking the time to answer our query.