Hi, first post here. Just acquired a 1998 4Runner SR5. I tried searching for a fix but no luck finding an issue similar to this.

The problem is with the power door lock system. At the driver side door the first twist of the key will unlock that door like normal but the second twist of the key will only unlock the driver side rear, the passenger side doors remain unaffected. When you twist to lock it only locks the driver side front door and non of the rest. This is only using the key on the driver side. The passenger side will lock and unlock all doors like normal.

Also the power door lock switch in the drivers side door panel, the unlock button only unlocks the drivers side doors, the passenger side doors remain unaffected. The lock button doesn't work whatsoever. So basically we are forced the manually lock and unlock all doors or use the passenger side door lock to lock all doors.

On my Hondas the typical fix is to clean the contacts at the switches. This did not work at all on the 4Runner. I know all the power door lock actuators work (as tested using the passenger side key lock) so I'm thinking it's an electrical issue somewhere in the system. This is where I'm stumped on what to do next. Anyone with similar issues or advice on what to check/fix/replace next? Thanks.