The fuel pump relay on a Honda Rancher 420 is located in the fuse/relay box under the seat on the left side near the battery. It’s a standard 5‑pin relay labeled FUEL PUMP in most fuel-injected models.
Location and access
The Rancher 420’s electrical box is typically tucked behind the left-side panel beneath the seat. Access usually requires removing the seat and the left panel to reveal the main fuse/relay block where the fuel pump relay sits alongside other relays and fuses.
Steps to access:
- Remove the seat by lifting the latch to unlock the seat panel.
- Open the left-side panel to expose the fuse/relay box.
- Identify the fuel pump relay, usually a 5‑pin unit labeled "FUEL PUMP" near the ECU/other relays.
- Carefully disconnect the wiring harness connector from the relay if you need to test or swap it.
Concluding: Once you locate the relay, you can test its operation or swap in a known-good relay to diagnose fuel-delivery issues.
Testing and replacement guidance
To verify or replace, follow these steps. This helps confirm whether the relay is at fault or if the issue lies elsewhere in the fuel system.
Before you begin, ensure the ATV is off, the key is removed, and the electrical system is de-energized to avoid shock or shorts.
- Check the fuse block for the corresponding fuse if the fuel pump does not prime when the key is turned to RUN.
- Swap the fuel pump relay with a known-good 5‑pin relay of the same rating to test behavior. If the engine starts or the pump primes with the swapped relay, the original relay is faulty.
- Listen for a buzzing or humming from the fuel pump shortly after turning the key to RUN; no sound can indicate a faulty pump or relay.
- Use a multimeter to verify voltage at the fuel pump connector when the relay is energized; you should see 12V at the pump when RUN/START is commanded.
Concluding: If swapping relays or testing voltage confirms the relay failure, replace with the proper Honda OEM or equivalent 5‑pin relay. If the pump has no power even with a good relay, inspect the wiring or ECU signals.
Notes on model year variations
Some early Rancher 420 variants or non‑FI versions may have different electrical layouts or may not use a separate fuel pump relay in the same way. For these cases, consult the specific year manual or service guide to confirm the exact location and component labeling. In most fuel-injected 420 models, the left-side under-seat fuse block is the standard location.
Concluding: For the majority of Rancher 420 FI models, the fuel pump relay sits in the main fuse/relay box under the seat on the left side near the battery; carbureted variants may differ or lack a dedicated fuel pump relay.
Summary
In most Honda Rancher 420 fuel-injected models, the fuel pump relay is found in the fuse/relay box under the seat on the left side, adjacent to the battery. It’s typically a 5‑pin relay labeled "FUEL PUMP." Access requires removing the seat and left panel; testing involves swapping with a known-good relay and checking for 12V at the pump when the ignition is in RUN/START. Always verify the exact layout for your specific year and model in the owner's or service manual.