I’ve had to replace two of the door lock actuators on my 2004 Acura MDX. I wasn’t sure how long they were broken because their failure mode was to not lock instead of not unlocking. The first time it was the rear passenger door and the second time it was the front passenger door.
It seems that the motor burns out and you can just replace it but I went the route of replacing the entire actuator assembly which was about $35. The part number for all the actuators except the driver’s front is 72115-S84-A11 and the drivers front is 72155-S84-A11
The rear actuator was a lot easier than the front actuator.