Cooling Fan Relay

This procedure covers the diagnosis, removal, and replacement of the cooling fan relay on a 2022 Rivian EDV 500, which controls the operation of the electric cooling fans for the battery and motor cooling systems.

Warnings

Tools required

Parts

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Power down the vehicle completely and remove key fob from the cabin
3. Wait at least 5 minutes for all vehicle systems to enter sleep mode
4. Open the front hood and secure with hood prop
5. Disconnect the 12V auxiliary battery negative terminal and isolate the cable
6. Verify high-voltage system isolation by checking the instrument cluster does not illuminate when attempting to power on
7. Document the current fault codes using Rivian diagnostic software or OBD-II scanner
8. Test cooling fan operation before disassembly to confirm relay failure (if possible with diagnostic tool commanding fan operation)

Procedure

1. 1

   Access the power distribution module
   Locate the front power distribution module (PDM) in the front trunk area on the driver's side. Remove the plastic access cover by releasing the clips using plastic trim tools. The PDM houses multiple relays and fuses for vehicle electrical systems.
2. 2

   Locate the cooling fan relay
   Reference the relay diagram on the underside of the PDM cover or in the vehicle service manual to identify the cooling fan relay position. On the EDV 500, this is typically position R7 or R8 in the front PDM. The relay should be labeled 'COOL FAN' or similar designation.
3. 3

   Document relay connector orientation
   Before removal, photograph or document the relay orientation and connector pin layout. Note the position of pin 1 (typically marked on the relay base) for proper reinstallation of the new relay.
4. 4

   Remove the failed relay
   Grasp the relay body firmly and pull straight up with steady pressure to extract it from the socket. Do not rock or twist the relay, as this can damage the socket terminals. If the relay is difficult to remove, use needle-nose pliers to grip the sides while pulling upward.
5. 5

   Inspect the relay socket
   Examine the relay socket terminals for signs of burning, corrosion, discoloration, or damage. Check that all spring terminals are present and have proper tension. If terminals are corroded, clean with electrical contact cleaner and allow to dry completely. If terminals are burned or damaged, the socket assembly must be replaced.
6. 6

   Test the failed relay
   Using a multimeter set to continuity mode, test the old relay by applying 12V across the coil terminals (typically pins 85 and 86) and checking for continuity between the switched terminals (typically pins 30 and 87). The relay should click audibly when energized. If no click occurs or no continuity is present when energized, the relay has failed.
7. 7

   Verify circuit integrity
   With the relay removed, use a multimeter to check for battery voltage at pin 30 of the relay socket (power supply). Check for proper ground at pin 85. Verify the control signal circuit at pin 86 shows approximately 0V at rest. This confirms the circuit is intact and the relay was the failure point.
8. 8

   Prepare the new relay
   Remove the new relay from its packaging and verify it matches the OEM specifications including part number, amperage rating, and pin configuration. Apply a thin coating of dielectric grease to the relay terminals to prevent corrosion and ensure good electrical contact.
9. 9

   Install the new relay
   Align the new relay with the socket ensuring pin 1 matches the documented orientation. Press the relay firmly and evenly into the socket until it seats fully and clicks into place. Verify all pins are properly engaged and the relay is secure.
10. 10

    Reconnect the 12V battery
    Return to the 12V auxiliary battery and reconnect the negative terminal. Tighten the terminal connection securely. The vehicle systems will initialize and may take 1-2 minutes to complete startup procedures.
11. 11

    Clear fault codes and test operation
    Connect the diagnostic software or OBD-II scanner. Clear any stored fault codes related to cooling fan operation. Use the diagnostic tool to command the cooling fans to activate at various speeds (low, medium, high if applicable) and verify proper operation. Monitor for proper current draw and listen for smooth fan operation without unusual noise.
12. 12

    Reinstall access covers
    Replace the PDM access cover ensuring all clips engage properly. Verify the cover is fully seated and secure. Remove tools and close the front hood.

Reassembly

1. Ensure all electrical connections are secure and properly seated
2. Verify the PDM cover is completely installed with all retention clips engaged
3. Confirm no tools or parts remain in the front trunk area
4. Return any diagnostic equipment to storage

Verification

• With vehicle powered on, verify no warning lights or messages appear related to cooling system faults
• Monitor the cooling fan operation during a short test drive or while vehicle is stationary in Ready mode
• Use diagnostic software to verify cooling fan responds correctly to commanded operation at all speed ranges
• Check that cooling system temperatures remain within normal operating range (typically 40-60°C for EV cooling systems)
• Verify no new fault codes are present after test operation
• Confirm relay does not exhibit excessive heat after 10-15 minutes of operation by carefully touching the relay body (should be warm but not hot)

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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