I rechecked, and it appears that the brake lights DO work (my wife wasn't pressing down on the brakes hard enough the first time I checked). Also, the first time I tested, the side marker lamps were working, but now they aren't (making me think I've got a loose wire somewhere). So now everything works except for my tail lights and (sometimes) my side marker lights. I'll try the tests you recommended and see if I can find anything. Thanks.