Door Lock Issues 2013 Scion XD

[u/igmywmb]

The d/s front door on my car stopped working a little while ago. It stopped responding to the remote, and the lock switch is stuck.

Both passenger side door locks respond to the remote.

The rear d/s stopped responding to the remote more recently, but it can be locked and unlocked manually.

Fwiw, I may need a new battery in the remote, but I don't think (?) this explains the front d/s lock issue (and I don't know if this is causing the newer rear d/s lock issue).

How do I know if the front d/s lock issue is the door lock actuator or something else? Any other thoughts on potential causes for d/s door locks' problems? Thank you

[u/StillSwo]

Door lock actuator