Ive got a 1989 tw200 with a electrical problem. The blinkers dont work at all. They started not working by blinking slow, so i changed the bulb it worked. Now 8 months laster none of the blinkers work. I check for continuity on the two wires going to each rear turn signal which is showing they are good, closed circuit(each rear turn signal only has two wires) Where should else should i start?