Auto body repair & detailing: 1996 GMC Jimmy Back Door Unlock Problem., salvage yard, gmc jimmy

Question
I am not able to unlock the back tailgate of my 1996 GMC Jimmy.  Is there any way to open the door.  I have tried to use a screw driver from the inside back by pulling the carpet piece and manually unlock the back door.  The dealership mentioned an (agulator?).  Can you please advise if I will be able to replace this and if I could locate this at a salvage yard.  And do you know about how much this part cost.  OR do you have any suggestions for me opening the door and unlatching it.  Thanks!

Answer
You may be able to take off the tailgate trim panal from the inside , once the trim panal is removed, take a flashlight and look on the inside of the tailgate for the lock mechanism.  Try and lubricate the lock mechanism with penatrating oil and then grease once the latch is working. If you can't get the latch to work than you may be able to get a used one at a salvage yard for about 30 to 40 bucks. This may not be a easy job for a novice.
               Thank you for the question!
               Ken