[Lifetime Warranty] SW1951C Heavy Duty Starter Solenoid Relay - Compatible with Ford F150 F250 F350 F450 F550 E150 E250 E350 Escort Bronco Mustang Ranger & Mercury & Lincoln - E5TZ-11450-A E9TZ-11450-B SW1951

SW1951C Heavy Duty Starter Solenoid Relay

Key Features

• High-current capacity designed to handle heavy electrical loads for reliable engine cranking in gas and diesel applications.
• Corrosion-resistant copper terminals for superior conductivity and long-term durability in harsh environments.
• Heavy-duty internal contact plates engineered for rapid heat dissipation and arc suppression.
• Robust weather-sealed housing protects internal components from engine bay contaminants and moisture.
• Standard four-post configuration (two high-current studs and two signal terminals) for direct system integration.

Replaces / Cross-Reference Part Numbers

• SW1951C
• SW1951
• E5TZ-11450-A
• E7TZ-11450-A
• E9TZ-11450-B
• F3TZ-11450-B
• B6AZ-11450-A
• 311000
• F1722

Compatibility & Fitment

• Ford Trucks & Vans:F-150, F-250, F-350, F-450, F-550 Super Duty, E-150, E-250, E-350 Econoline, Bronco, and Ranger.
• Ford Cars:Mustang, Escort, Crown Victoria, Explorer, Thunderbird, and Taurus.
• Mercury:Grand Marquis, Cougar, Mountaineer, Capri, and Sable.
• Lincoln:Town Car, Navigator, Mark VII, Mark VIII, and Continental.
• Fits a wide range of Ford-family vehicles typically manufactured between the 1980s and early 2000s.
• Compatible with 12V DC starting systems.

When to Replace

• Engine fails to crank or start despite a fully charged battery and functional ignition switch.
• Rapid "clicking" sound heard from the engine bay when turning the key to the start position.
• Starter motor remains engaged or continues to spin after the engine has started or the key is released.
• Intermittent starting issues, particularly during extreme temperature fluctuations.
• Visible signs of heat damage, melting, or heavy oxidation on the solenoid terminals.

Installation Tips

• Disconnect the negative battery cable before beginning the replacement to prevent electrical shorts.
• Clearly label or photograph the wire placement on the existing solenoid before removal to ensure correct reconnection.
• Clean the existing wire ring terminals with a wire brush or sandpaper to ensure a solid metal-to-metal connection.
• Mount the solenoid securely to the vehicle fender well or firewall; the mounting bracket often serves as the chassis ground.
• Tighten the terminal nuts firmly to prevent arcing, but do not over-torque to avoid cracking the plastic solenoid housing.
• Re-apply any original protective rubber boots or covers to the terminals after installation.