I did my required Google-ing and searches on this site and never found an issue quite like mine...

2003 Accord EX, about 145K miles.

About a year ago, the back passenger side door would not lock. So now I just keep it locked and if I ever need it open, I reach back to unlock it.

About 6 months ago, the front passenger side door stopped responding to a lock command. But the funny thing was, when it started to show signs of weakness, I could press lock (on driver side door or remote) about 5 or 6 times and it would eventually makes its way down or up. Eventually, it just stopped working altogether.

So now I have 2 out of 4 doors that lock and unlock remotely or by the master unlock/lock button on the driver's side.

I have found NO other issues with the car that would seem related to this. The AC has stopped blowing cold air but it did this last summer too (and fixed itself) so I think that is unrelated.

I am happy, willing, and able to do any minor fixes myself on the car.
Thanks in advance!

 

If I had to guess, it would be the door lock actuator. To test, you would have to remove the door panel on the lock that is not working. Unplug the actuator. Use connect a 12V test light across the connector and see if the bulb lights up when you try to lock/unlock that door.