I have a wierd electrical problem and I'm not sure where to start. I have no power to the dash lights, blinkers, or heater controls. When I start the car the fuel and temp guages work fine, but if I try to turn on the blinker or heater the guages quit working all together until the car is restarted. I checked all the fuses and none of them are blown. I can't se any damaged or broken wires. Any ideas on how to diagnose this??