Where is the relay for the cooling fan?
Usually in the engine bay, inside the main fuse/relay box and labeled FAN or Radiator Fan; some models position the relay in the interior fuse panel or in a centralized relay module. Exact location varies by make and year.
Common locations to check
Before you start testing wires, know the typical spots where the cooling fan relay appears. This helps you zero in quickly and safely.
- Under-hood fuse/relay box: The most common location. Look for a relay labeled "FAN," "FAN RELAY," or "RADIATOR FAN" on the box cover or in the diagram printed on the box.
- Interior fuse/relay panel: Some models place the relay inside the cabin, often beneath the dashboard near the driver’s knee or behind a trim panel.
- Engine bay relay module: In newer vehicles, a centralized relay module may house one or more cooling fan relays near the radiator or firewall.
- No dedicated relay in some designs: A few modern vehicles control the fan directly through the engine control unit (ECU) or use a solid-state switch instead of a conventional mechanical relay.
Knowing these locations can save time when diagnosing a fan that won’t run or when replacing a faulty relay.
How to identify the exact location for your vehicle
To pinpoint the relay for your specific model, follow these practical steps. They leverage the car’s own documentation and common factory layouts.
- Consult the owner’s manual or a factory repair guide for the fuse/relay diagram. Look for references to "FAN," "Radiator Fan," or "A/C Fan."
- Inspect the under-hood fuse box first; diagrams are often on the inside of the lid or nearby on a label.
- Trace the cooling fan wiring toward the nearest relay socket; a typical relay has 4 or 5 pins and a distinct plug.
- If still unsure, search for the exact make, model, and year online or contact a dealership; there are sometimes model-specific quirks.
When working with electrical components, prioritize safety: disconnect the battery before swapping relays and use a known-good relay to confirm diagnosis.
Vehicle-type notes
Gasoline-powered cars
Most gasoline vehicles feature a dedicated radiator fan relay in the under-hood fuse/relay box, occasionally with separate relays for low and high speed. In many modern cars, the relay is clearly labeled and easy to locate.
Hybrid and electric vehicles
Hybrids and EVs may control cooling fans via the motor control unit or battery management system, with fewer or differently located relays. If a relay exists, it may be part of a specialized relay module rather than a standard under-hood box.
Summary
Locating the cooling fan relay generally means starting with the under-hood fuse/relay box and looking for labeling like "FAN" or "Radiator Fan." If it isn’t there, check interior fuse panels or a centralized relay module, and consult the vehicle’s manual for model-specific diagrams. With careful testing and the right references, you can identify, test, and replace the relay to restore cooling fan operation.
