79 Ford Ignition Switch Wiring

The ignition switch in a 1979 Ford is a critical component responsible for starting the engine and powering the vehicle’s electrical systems. Understanding the 79 Ford ignition switch wiring is essential for maintenance, troubleshooting electrical problems, or performing repairs. This guide provides a detailed overview of the wiring, its function, and practical steps for diagnosing and resolving common issues.

Benefits of Understanding Your 79 Ford Ignition Switch Wiring

Familiarizing yourself with the 79 Ford ignition switch wiring offers numerous advantages:

• Accurate Diagnostics: Properly identify the source of electrical issues related to starting or power distribution.
• Cost Savings: Perform DIY repairs and avoid expensive mechanic fees.
• Improved Vehicle Reliability: Prevent minor issues from escalating into major problems.
• Enhanced Safety: Ensure proper functioning of safety-critical systems connected through the ignition switch.
• Increased Vehicle Knowledge: Gain a deeper understanding of your classic Ford’s electrical system.

Key Components and Wiring Diagram Understanding

The ignition switch assembly connects to various wires responsible for different functions. Key circuits and wires include:

• Battery (BAT): Supplies power from the battery to the switch. Typically a heavy-gauge red wire.
• Ignition (IGN): Powers the ignition system, including the coil and distributor. Often a pink or red/green wire.
• Accessory (ACC): Powers accessories like the radio, wipers, and heater. Usually a yellow or brown wire.
• Start (STR): Activates the starter solenoid to crank the engine. Commonly a red/blue or purple wire.

A wiring diagram is crucial for identifying each wire and its corresponding function. Wiring diagrams for 79 Ford models are available in service manuals and online resources. Always refer to the correct diagram for your specific vehicle configuration.

Practical Applications

Understanding the 79 Ford ignition switch wiring allows for effective troubleshooting and replacement. Here’s a general process:

1. Identify the Problem: Common symptoms of a faulty ignition switch include:
   • Engine not starting
   • Accessories not working
   • Engine stalling
   • Key getting stuck
2. Inspect the Wiring: Visually check for damaged, corroded, or loose wires at the ignition switch connector.
3. Test for Power: Use a multimeter to verify power at the battery terminal (BAT) of the ignition switch.
4. Check Continuity: With the ignition switch in different positions (OFF, ACC, ON, START), use a multimeter to check for continuity between the BAT terminal and other terminals (IGN, ACC, STR). Refer to the wiring diagram to understand which terminals should have continuity in each position.
5. Replace the Switch: If the switch is faulty, disconnect the battery, carefully disconnect the wiring harness, remove the old switch, and install the new one. Reconnect the wiring harness and battery.

1. Troubleshooting Common Ignition Switch Issues

Here are some troubleshooting tips related to 79 Ford ignition switch wiring:

• No Start Condition: Verify power at the BAT terminal. Check the starter solenoid and wiring.
• Accessories Not Working: Check the ACC terminal for power when the ignition is in the ACC or ON positions.
• Intermittent Stalling: Check for loose wiring or a faulty ignition module.
• Key Stuck in Ignition: This could indicate a worn ignition cylinder or a mechanical problem within the switch assembly.

2. Tips for Working with 79 Ford Ignition Switch Wiring

• Disconnect the Battery: Always disconnect the negative battery cable before working on any electrical components.
• Use a Multimeter: A multimeter is essential for testing voltage and continuity.
• Consult a Wiring Diagram: Always refer to the correct wiring diagram for your vehicle model and year.
• Label Wires: When disconnecting wires, label them to ensure correct reassembly.
• Inspect Connectors: Carefully inspect connectors for corrosion or damage.

Frequently Asked Questions (FAQs)

• Q: Where can I find a wiring diagram for my 79 Ford?

  A: Wiring diagrams are available in service manuals, online forums, and some parts suppliers may offer them as well.

• Q: What tools do I need to replace an ignition switch?

  A: Typically, you’ll need a screwdriver set, pliers, a multimeter, and possibly a steering wheel puller (depending on the model).

• Q: Is it safe to bypass the ignition switch for testing?

  A: Bypassing the ignition switch can be dangerous and is not recommended unless you have advanced electrical knowledge. Improper bypassing can damage the vehicle’s electrical system.

• Q: Can I use an ignition switch from a different year Ford?

  A: It’s crucial to use an ignition switch that is specifically designed for your 1979 Ford model. Using a different year switch can lead to wiring incompatibilities and electrical problems.

Conclusion

Understanding the 79 Ford ignition switch wiring is a valuable skill for any classic Ford owner. By familiarizing yourself with the wiring diagram, diagnostic procedures, and replacement steps, you can effectively troubleshoot electrical issues, perform DIY repairs, and maintain the reliability of your vehicle. Remember to always prioritize safety and consult a qualified professional if you are unsure about any aspect of the repair process.