Try to lubricate every thing to do with the locks with a good penetrating/ lubricating oil but it sounds like some lock actuators are bad. If it is something you want to investigate yourself there is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online