Standard Ignition RY-78 Horn Relay

Horn Relay for Ford and Mercury Applications

Standard Ignition RY-78 is a 12-volt horn relay built for vehicles that need reliable electrical switching in demanding underhood conditions. It uses a 3-terminal blade design with a rectangular female connector and 30 amp amperage rating for direct relay service on select Ford, Lincoln, and Mercury applications.

Key Features

• 12-volt horn relay with 30 A amperage rating
• 3-terminal blade connection with female rectangular connector
• Composite housing helps protect against heat and harsh underhood exposure
• Brass or copper contacts are used where specified for wear resistance
• Manufactured under TS16949 and ISO9001 certified quality systems
• Standard Ignition RY-78 replacement part number for service and repair

Detailed Product Overview

The Standard Ignition RY-78 horn relay is built for electrical relay service where consistent switching performance matters. Standard Ignition manufactures this relay with controlled quality processes and OE-focused production standards, helping ensure the correct fit and function for the listed vehicles. This part cross-references Bosch 16134 for the same application. Use RY-78 when servicing horn relay circuits on select Ford F-150, Ford F-250, Ford F-350, Ford Ranger, Ford Mustang, and related Lincoln and Mercury models.

What This Relay Helps Address

• Horn inoperative due to relay failure
• Intermittent horn operation from worn relay contacts
• Electrical switching issues in the horn circuit
• Heat-related relay breakdown in the engine compartment
• Replacement needs on aging Ford, Lincoln, and Mercury electrical systems

Installation Notes and Fitment

Compatible With select 1984-1995 Ford, Lincoln, and Mercury vehicles. Fits 1995 Ford F-150, N/A; Fits 1987-1993 Ford F-150, N/A; Fits 1995 Ford F-250, N/A; Fits 1987-1993 Ford F-250, N/A; Fits 1995 Ford F-350, N/A; Fits 1987-1993 Ford F-350, N/A; Fits 1991-1994 Ford Explorer, N/A; Fits 1986-1994 Ford Ranger, N/A; Fits 1985-1994 Ford Tempo, N/A; Fits 1984-1994 Lincoln Continental, N/A; Fits 1984-1994 Mercury Topaz, N/A; Fits 1984-1993 Ford Mustang, N/A; Fits 1987-1992 Ford Aerostar, N/A; Fits 1987-1991 Ford Bronco, N/A; Fits 1984-1991 Ford Escort, N/A; Fits 1986-1991 Mercury Cougar, N/A; Fits 1991 Mercury Tracer, N/A; Fits 1987-1989 Mercury Tracer, N/A; Fits 1987-1990 Ford Bronco II, N/A; Fits 1984-1989 Ford Thunderbird, N/A; Fits 1984-1989 Lincoln Town Car, N/A; Fits 1987-1988 Ford E-150 Econoline, N/A, Brake Light Switch for vehicles with Cruise Control; Fits 1987-1988 Ford E-150 Econoline Club Wagon, N/A, Brake Light Switch for vehicles with Cruise Control; Fits 1987-1988 Ford E-250 Econoline, N/A, Brake Light Switch for vehicles with Cruise Control; Fits 1987-1988 Ford E-250 Econoline Club Wagon, N/A, Brake Light Switch for vehicles with Cruise Control; Fits 1987-1988 Ford E-350 Econoline, N/A, Brake Light Switch for vehicles with Cruise Control; Fits 1987-1988 Ford E-350 Econoline Club Wagon, N/A, Brake Light Switch for vehicles with Cruise Control; Fits 1985-1987 Mercury Lynx, N/A; Fits 1986 Ford Aerostar, N/A, w/ Speed Control; Fits 1986 Ford Bronco II, N/A, w/ Speed Control; Fits 1984-1986 Ford LTD, N/A; Fits 1985-1986 Mercury Capri, N/A; Fits 1984-1986 Mercury Grand Marquis, N/A, 3 Terminal Manifold Absolute Pressure Sensor; Fits 1985-1986 Mercury Marquis, N/A; Fits 1984 Mercury Capri, N/A, OE No. E6FZ-A. Verify connector shape, terminal count, and circuit layout before installation. The RY-78 uses a female rectangular connector with 3 male blade terminals and no mounting bracket.

Quality Assurance

Standard Ignition manufactures this relay under stringent quality requirements with composite housings selected for harsh temperature and underhood exposure. TS16949 and ISO9001 certified production supports consistent part control from component sourcing through finished product.