Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2004 Honda S2000 L4-2.2LFACTORY OEM SERVICE PROCEDURE
Cooling System: Description and Operation
How the Circuit Works
Voltage is provided at all times to the radiator fan relay contacts through fuse 57, and to the A/C condenser fan relay contacts through fuse 58. With the ignition switch ON (II) and the engine not cranking, voltage is provided to the coils of the relays through fuse 20.
The relays are grounded by either the radiator fan switch or by the ECM. Grounding the relays energizes their coils and applies battery voltage to the radiator and condenser fan motors. Both fans then run until ground is removed from the relay coils.
Voltage is provided at all times to the radiator fan relay contacts through fuse 57, and to the A/C condenser fan relay contacts through fuse 58. With the ignition switch ON (II) and the engine not cranking, voltage is provided to the coils of the relays through fuse 20.
The relays are grounded by either the radiator fan switch or by the ECM. Grounding the relays energizes their coils and applies battery voltage to the radiator and condenser fan motors. Both fans then run until ground is removed from the relay coils.
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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