the dealership is gonna rape u......at least they always try... anyhow, u might wanna pop the inside door panels off and try cycling the door locks to see if there is anything that is catching or rubbing or generally impeding the mechanism. if nothing is physically wrong, then at least u will be able to pin point the problem. if the solenoid is trying to actuate but not quite making it, then u know u gotta replace that. my suggestion is to find replacement parts online like ebay or something and put them in urself, it's easy and saves u a lot of loot.