* Battery Positive (+): A heavy-gauge wire directly from the positive battery terminal. This provides the high current needed to activate the solenoid. This is usually a very thick, red wire.
* Starter Motor (+): A heavy-gauge wire from the solenoid to the starter motor. This also carries a high current, and will also likely be a thick, red wire.
* Ignition Switch ("S" terminal): A smaller-gauge wire from the ignition switch's "S" (start) terminal. This wire sends the low-current signal to energize the solenoid, allowing the high-current circuit to close. This wire is usually a lighter gauge than the battery and starter wires.
* Sometimes a Ground (-): While the solenoid is often grounded through its mounting, some installations may have a separate ground wire. This would be a black wire connected to a clean ground point on the engine block or chassis.
Important Considerations:
* Heavy Gauge Wiring: The wires connected to the battery and starter motor MUST be heavy gauge to handle the high amperage. Using too thin of a wire could cause overheating, damage, and potentially a fire.
* Color Codes: While generally red for positive and black for negative, color codes aren't always consistent. Always trace the wires to confirm their origin and destination.
* Wiring Diagram: The best way to be absolutely sure is to consult a wiring diagram specific to your 1969 Ford Mustang. These are available in repair manuals (like a Haynes or Chilton manual) or online through Mustang-specific forums and resources. These diagrams will provide details for your specific model and options.
Do not attempt to work on the electrical system without disconnecting the negative battery terminal first to prevent accidental shorts. If you're unsure about any aspect of automotive electrical work, it's always best to consult a qualified mechanic.
