STS Parts F540 Premium External Voltage Regulator delivers OEM-level performance for Ford, Lincoln, and Mercury vehicles equipped with 1G external alternators. This heavy-duty, solid-state regulator provides consistent voltage control, improved reliability, and extended service life compared to older mechanical or remanufactured units. Built to exacting standards and fully encapsulated for corrosion resistance, the F540 ensures stable 14.2V system output for efficient charging and safe electrical operation. Specifications System Voltage: 12V DC Circuit Type: B-Circuit / Negative Ground Set Point: 14.2V nominal (temperature-compensated) Terminals: I (Lamp), A (B+ Sense), S (Stator), F (Field) Housing: Fully sealed electronic unit Condition: 100% New Solid-State Activation: Ignition Cross-References: AFD6001, F540, GR540, GR540A, GR540B, GR785, GR803, VR508, 230-14004, 230-14007, Regitar GR540A, MFVR01150, D9PF-10316-AA, E2AF-10316-AA, and many others. Compatibility Summary: Compatible with Ford, Lincoln, and Mercury models (1964-1987) using the 1G external regulator alternator, including Mustang, F-Series trucks, Bronco, Fairlane, Torino, LTD, Thunderbird, Cougar, and other classic applications. Also fits select Jeep, AMC, and industrial units using the same connector pattern.