How to find the right Automotive Replacement Radiator Fan Relays AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Automotive Replacement Radiator Fan Relays
- Current capacity
- Equal to or higher than the OEM relay's current capacity; fan relays are typically heavy-duty ISO or high-current types Fan motors pull high inrush current, and undersized relays weld their contacts or melt the socket.
- Relay vs fan control module
- Confirm whether the fan uses relays or a PWM fan control module Many newer vehicles vary fan speed electronically, so buying a relay will not fix a failed module.
- Speed circuit
- On two-speed systems, identify which relay (low, high or series/parallel) failed and match each OEM number Two-speed systems use several relays with different roles, and the wrong one in a slot changes fan behavior.
- Socket condition
- Inspect the socket for browning or melted plastic before fitting a new relay A heat-damaged socket will quickly destroy a new relay.
Brands that matter
- Bosch: Heavy-duty ISO relays common in European and aftermarket fan circuits.
- Hella: OE-type ISO relays, also widely used in aftermarket fan wiring.
- Standard Motor Products: Application-specific fan relays with cross-references.
- Denso: OE-type relays for many Japanese vehicles.
- ACDelco: OE-equivalent for GM.
What to avoid
- Lower-capacity relays chosen only because the pins fit
- Running the fan with a jumper as a permanent fix
- Ignoring a scorched relay socket or fusible link
Questions
Fan does not run: relay, motor or sensor?
Check the fan fuse, then swap the relay with an identical one. If the fan still does not run, apply power directly to the fan to test the motor before suspecting the temperature sensor or ECU command.