When the switch is pushed for example to the unlock position the unlock wire gets disconnected from the ground and connected to 12v activating the actuator.
How to test for 5 wire door locks.
How to wire automotive spdt relays.
Step 2 activate the power lock switch to its lock and unlock positions while listening for a distinctive click sound coming from the relay.
The switch when moved in either direction applies both power and ground directly to motor legs without the use of any relays.
If you cannot hear the click go to the next step.
Except at the switch in this case both motor legs rest at ground.
While the switch is off both wires lock and unlock are grounded.
Some of these will open a circuit to lock and ground a wire to unlock.
Single wire door lock systems type f type g type h there may be one two or three wires in the harness not counting the illumination wire s if any and only changes in voltage and or resistance on one wire to lock and unlock.