882751A04 Relay Assembly for Mercury Mercruiser Mariner | JLM Marine

882751A04 Relay Assembly for Mercury Mercruiser Mariner

This 882751A04 Relay Assembly is engineered for reliable electrical performance across a wide range of Mercury, Mercruiser, and Mariner marine engines. It fits Mercury Verado outboards (135HP to 400HP), Mercruiser 8.1L 496 CID inboard/sterndrive engines, and joystick piloting system harnesses for both single and dual-engine rigging applications.

This relay directly replaces OEM part numbers 821509, 821509T01, 853292, and 882751A04, as well as aftermarket equivalents from Sierra Marine (18-5850, 18-5852), Mallory (9-15212), and Chrysler/Force/US Marine (821509). It serves as a critical electrical switching component in PCM modules, electrical box assemblies, and joystick control systems.

• Direct OEM replacement for multiple Mercury, Mercruiser, and Mariner platforms
• Compatible with Verado outboards, 8.1L sterndrive engines, and joystick piloting systems
• Precision-built to factory specifications for reliable electrical switching

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands:

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 × Relay Assembly (882751A04)

Installation Guide

1. Disconnect the battery – Turn off all power sources and disconnect the negative battery terminal to ensure safety during installation.
2. Locate the existing relay – The relay is typically mounted in the electrical box, PCM bracket, or joystick control harness assembly. Refer to your engine's wiring diagram for exact placement.
3. Remove the old relay – Carefully disconnect all wire terminals from the old relay, noting their positions. Remove any mounting screws or clips securing the relay.
4. Inspect terminals and wiring – Check all terminals and connectors for corrosion, damage, or loose connections. Clean or replace as needed.
5. Install the new relay – Position the new 882751A04 relay in the mounting location and secure it with screws or clips.
6. Connect wire terminals – Attach all wire terminals to the corresponding posts on the new relay, ensuring a tight and secure fit.
7. Verify connections – Double-check all electrical connections against your wiring diagram to confirm correct installation.
8. Reconnect the battery – Reconnect the negative battery terminal and restore power to the system.
9. Test functionality – Turn on the ignition and test electrical systems (starter, joystick controls, or PCM functions) to ensure the relay is operating correctly.
10. Inspect for abnormalities – Listen for unusual clicking sounds or check for overheating during initial operation. If issues arise, recheck all connections.

Troubleshooting & FAQ

Q: How do I confirm this relay fits my engine?
A: Cross-reference your engine's serial number and model year with the compatibility table above. Also verify that your original relay's part number matches one of the replacements listed (821509, 821509T01, 853292, or 882751A04). The Mercury Serial Number Guide linked above can help you locate your engine details.

Q: What are the signs that my relay needs replacement?
A: Common symptoms include intermittent electrical failure (starter not engaging, joystick controls unresponsive), clicking sounds when turning the key, burning smell near the electrical box, or complete electrical system failure. If the relay feels excessively hot or shows visible burn marks, replace it immediately.

Q: Can I use this relay on both single and dual engine joystick systems?
A: Yes, this relay is compatible with both single-engine and dual-engine joystick piloting system harness assemblies for Mercury, Mercruiser, Mercury Sportjet, and Force applications, as listed in the compatibility table.

Q: How often should this relay be inspected or replaced?
A: Relays typically last several years under normal use. Inspect the relay annually during routine maintenance, checking for corrosion, loose connections, or physical damage. Replace immediately if you notice any electrical malfunctions or if the relay shows signs of overheating or burning.

Q: Will this work with my Verado's electrical box?
A: Yes, this relay is designed for Verado electrical box components across 135HP to 400HP models and various serial ranges. Confirm your specific serial number in the compatibility table to ensure fitment.

Q: What's the difference between OEM and aftermarket relays?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.