The headlamp control module is under the wheelarch liner of the left hand front wheel. Starting by loosening the left hand side front wheel nuts and chocking the rear wheels. Jack the front of the car up and place it on the axle stands, remove the front roadwheel and undo the six screws holding on the front part of the wheelarch liner. Next, reverse the direction of the securing screws, undo the locking catch and remove the wiring plug to remove the module. For refitting, do it the opposite order of removal. If a new module is installed, suitable software should be downloaded and installed which should be left to a Volvo dealer or suitably equipped specialist.