Unplug the door lock actuator electrical connector.
Rear door lock actuator rx300 fix.
Place the lock and actuator assembly with the cables attached back into the door.
Clean and reconnect the actuator.
You should see the voltage polarity toggle with each switch activation.
Door lock systems operate the actuator by toggling positive negative voltage to the actuator.
Door lock actuator motor fits rear left drive side rear right passenger side for 1998 2005 gs300 1998 2000 gs400 2001 2005 gs430 rx300 4 2 out of 5 stars 23 25 99 25.
This low cost method works great and can be done on many cars.
Install the white plastic cover back onto the lock and actuator assembly by securing it with the two other screws you removed previously.
Then use your test light or digital meter to check for power and ground at the connector when you operate the lock unlock switch.