Cooling Fan Relay

This procedure replaces the cooling fan relay on a 2025 Rivian EDV 500 Dual Motor AWD electric delivery van, controlling the electric motor and battery cooling system operation.

Warnings

Tools required

Parts

• Cooling fan relay × 1 — Use OEM specification
• Relay socket connector (if damaged) × 1 — Use OEM specification
• Dielectric grease × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off vehicle completely and remove key fob from cabin
3. Allow cooling system to cool for minimum 30 minutes if vehicle was recently operated
4. Verify high-voltage system is powered down using instrument cluster display
5. Open hood and secure with prop rod
6. Disconnect 12V auxiliary battery negative terminal and wait 2 minutes for system capacitors to discharge
7. Use scan tool to document any existing fault codes related to cooling system
8. Take photos of relay location and wire routing for reference during reassembly

Procedure

1. 1

   Access front electrical compartment
   Remove the front electrical compartment cover located on the driver side of the engine bay. Remove four T30 Torx screws securing the plastic cover. Carefully lift cover away from vehicle and set aside in a clean area.
2. 2

   Locate cooling system relay panel
   Identify the cooling system relay panel mounted to the inner fender well. The panel contains multiple relays for various cooling fans and pumps. The cooling fan relay is typically labeled on the panel cover or relay body with 'COOL FAN' or similar designation. Reference the vehicle service manual diagram if relay position is unclear.
3. 3

   Remove relay panel cover
   Release the relay panel cover by pressing down on the locking tabs at each end and lifting upward. The cover protects the relays from environmental contamination. Set cover aside in a clean location.
4. 4

   Test relay operation before removal
   Using a digital multimeter, verify the relay is receiving power and ground. Check terminal voltages according to relay pinout diagram. This confirms the relay itself is the issue rather than wiring harness problems. Document voltage readings for comparison after installation.
5. 5

   Remove old cooling fan relay
   Grip the cooling fan relay firmly and pull straight upward with steady pressure to remove from socket. If relay is stuck, use a relay puller tool or carefully work needle nose pliers under the relay body edge. Do not pry against socket terminals as this can damage the connector. Inspect relay terminals for signs of heat damage, corrosion, or burning.
6. 6

   Inspect relay socket and wiring
   Carefully examine the relay socket connector for signs of melting, corrosion, or damaged terminals. Check that all socket terminals have proper spring tension and are not pushed back into the connector body. Inspect wiring harness for 6 inches back from connector for any signs of heat damage or worn insulation. If socket is damaged, it must be replaced before installing new relay.
7. 7

   Clean relay socket contacts
   Use electrical contact cleaner and a small brush to clean the relay socket terminals. Remove any corrosion or debris. Allow socket to dry completely before proceeding. This ensures proper electrical contact with the new relay.
8. 8

   Prepare new relay for installation
   Remove new cooling fan relay from packaging and verify part number matches original relay. Apply a small amount of dielectric grease to the relay terminals to prevent corrosion and ensure good electrical connection. Do not over-apply grease as excess can attract dirt.
9. 9

   Install new cooling fan relay
   Align the new relay with the socket, ensuring proper orientation by matching the relay key or tab with the socket slot. Push relay firmly into socket until it seats completely. You should feel or hear a slight click when relay is fully engaged. Verify relay cannot be pulled out easily with light upward pressure.
10. 10

    Verify relay installation and test operation
    Reconnect 12V auxiliary battery negative terminal. Turn vehicle to ON position without enabling drive mode. Monitor cooling fan operation using scan tool or by listening for fan activation. The thermal management system should activate fans based on component temperatures. If ambient temperature is cool, fans may not activate immediately. Use scan tool active tests if available to command fan operation and verify relay function.
11. 11

    Reinstall relay panel cover
    Position relay panel cover over relays and press down firmly until locking tabs engage on both sides. Ensure cover is fully seated to maintain environmental seal protecting relays from moisture and debris.
12. 12

    Reinstall electrical compartment cover
    Position front electrical compartment cover and align with mounting points. Install four T30 Torx screws and tighten evenly in a cross pattern. Do not overtighten plastic fasteners.

Reassembly

1. Ensure all covers are properly secured and sealed
2. Verify no tools or parts are left in engine compartment
3. Confirm 12V battery connection is clean and tight
4. Remove lockout/tagout devices if used for HV system

Verification

• Clear any stored fault codes using scan tool
• Start vehicle and allow thermal management system to initialize
• Monitor cooling fan operation through multiple drive cycles
• Verify no new fault codes are present after test drive
• Check that cooling system maintains proper operating temperature
• Confirm fan relay activates fans at appropriate temperature thresholds
• Listen for abnormal relay clicking or chattering during operation
• Use scan tool to verify cooling fan current draw is within specification (typically 5-15A depending on fan speed)

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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