I have a 1998 Chev Lumina and the rear brake lights and turn signals dont work. The running lights in the rear are ok and the upper rear deck brake light works when you press the brake pedal, but not the rear. If you try to wire in the tail brake lights directly from the working deck brake light, the electrical system goes wacky, for example the door locks go up and down.. Is the problem in the turn signal multi functional device or is the problem more serious?? (the bulbs have been changed)