Loud buzzing/grinding noise when doors locked?

[Keathbordeaux@aol.com]

I have a 2012 NV 2500 HD, high roof. Just today there is a loud buzzing sound in the driver door, whenever the van locks itself on takeoff or whenever I lock it with the door switches, or the remote. 
It almost sounds like gears grinding... Any clues what the issue is and how to fix it?

Thanks folks.

[Keathbordeaux@aol.com]

I figured it out, got a service manual on CD off of Ebay, took the door panel off, window and rear window track out.

Disconnected the lock actuator (integral with the door latch) and opened it up. The main gear sprocket had a broken return spring, so I ordered a new one from a dealer, one day delivery. Relatively easy fix, $205 part, saved $350 over having the dealer do it. 

If you get a wicked buzzing when you lock the door I highly recommend just replacing the actuator ASAP. I use the truck every day for work and didn't want to risk it failing to the point where I wouldn't be able to lock it.