Update 11/25/2020

I replaced the passenger side door actuator and now that door is working correctly as well. I can now confirm that the lock motors in the rear passenger doors and the tailgate are not working. The super lock motor, however, is working in all three of those locks. What I would like to understand better is how I had a failure of all five of them. Is it truly because the car was left unused for 9 months? Just trying to contemplate any other reason for all of them going out Perhaps somehow the lock motors were kept engaged and they burned up? Thoughts?

 

No, the reason is the brushes wear out in the motors. Because they all lock and unlock together, makes sense they all wear out at the same time.

 

I kinda got the same problem only when the heat is on defrost I got bags of heat and truck runs for a while I get in with the key and click the dash rocker lock unlock about 5 times to unlock doors some times it does it right away only started with 0 and -3 temps did not do in summer. u say the drivers door could be the problem it’s like a master lock to the rest I have spare locks on a spare disco 1 should I try them did you install brand new locks thanks

 

The drivers door connects through a separate relay than the other four locks. I replaced the driver and front passenger looks with new locks. I am currently waiting on the other three to get delivered, but those were purchased from a salvage yard and were tested prior to removal. The cold will for sure slow these motors down.

 

It would almost be statically impossible for them to all seize at the exact same time. After I get the other three remaining out (waiting for delivery). I will take them apart and diagnose the motor. The front passenger lock motor was completely seized. A simple brush failure would't exhibit that behaviour.