Very few of the Thunderbird's electrical circuits have fuses, and only the headlights have a circuit breaker (built into the headlight switch). For a little added safety add a circuit breaker that will protect everything. Take a trip to your friendly auto parts store and pick up a 35 to 40 amp circuit breaker. Remove the heavy yellow wire from the starter solenoid (the one that goes into the passenger compartment) and attach that wire to one side of the circuit breaker. Add another heavy wire (10 gauge minimum) between the circuit breaker and the solenoid. By adding this breaker in series with that yellow wire every electrical device in the car is protected (except for the starter motor). If a direct short to ground occurs anywhere in your car that circuit breaker will trip and protect the wiring.