In some cars a door lock actuator becomes noisy and produces a squeaking or buzzing noise when the power door locks are locked or unlocked.
Town and country door lock making noise.
A buzzing noise after the door locks or unlocks is the door actuator the reason the cost of replacement is 400 to 800 is because the time it takes to get to the actuator is about 20 30 for a professional and about 1 hour for a beginner that s just to get to the device.
If you hear the buzz when you press the lock and unlock buttons as well as when your speed hits 15 mph auto lock then you have a bad lock actuator and the latch in the sliding door will need to be replaced to resolve your issues.
They could have constructed this a new way and cut the time by 70 to 80 but that s not up to the laborers and engineers dont care about ease of access.
For some model years the actuator for the sliding door is available separately from the latch.
If the door lock actuators integrated into the door latch assembly are noisy and or not working the latch should be replaced.