You will need to remove the hatch panel to get to the hatch lock assembly...not an easy job, often the clips that retain the rear hatch to the metal will snap at a cost of about $10.00US to replace. If you dare to go this far be careful to write down the order of the connecting rods as they attach to the rear hatch assembly and to the hatch lock, key opener, interior hatch push lock button and interior hatch door handle. It's an ugly job. The cost for the hatch assembly can run from $100 to $180 depending upon the Volvo dealership. It's almost impossible to get this hatch assembly from a used parts source. If you do this job yourself celebrate with a cold beer or two.