I bought a used 2000 Discovery and the rear (back) door lock actuator worked for only a couple of days. I found a used one and have installed and it reacts exactly the same. When trying to use it there is a small sound and I can feel a slight vibration so I think it is getting power. Aside from the obvious that this one is also bad, is there anything else that I should check? All of the other locks work with the remote and the console switch. This one also works manually from the inside.

Thank you in advance for your help.

 

Sounds like you bought a bad used one. As long as you here it trying, it has full power to the system. Try locking or unlocking it a few times and see if it does in fact start working.

 

The place where I bought it is sending a new (used) one tomorrow.
Thanks again