Replace that switch. I went to the dealership to do that and I twice acquired defective switches and it was tough to get refunds on them. Those switches have failed a total of four times between the two V-70's I have owned. If you have a multi-meter or volt meter, there is a way to test the switch and verify that it is the master switch and not the individual switches causing the problem. Flip the switch upside down and with the meter set to "continuity" put the test leads at different points and toggle away. fcpgroton.com sold me a master switch that was made by another company ( not Volvo but made in the UK ) and it has held up fine for the last two years and looks identical to the old one.