Cooling Fan Relay

This procedure guides you through locating, testing, and replacing the cooling fan relay on a 2023 Rivian EDV 500 electric delivery van, which controls the operation of the battery and motor cooling fans.

Warnings

Tools required

Parts

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

Preparation

1. Park the vehicle on a level surface and engage the parking brake
2. Turn off the vehicle completely and remove the key fob from the cabin
3. Allow the vehicle to sit for at least 30 minutes if recently driven to let cooling systems depressurize and cool down
4. Open the front hood and secure it in the open position
5. Locate and disconnect the 12V auxiliary battery negative terminal (typically located in front trunk area)
6. Wait at least 5 minutes after battery disconnect for capacitors to discharge
7. Have Rivian wiring diagrams available to identify the specific cooling fan relay (there may be multiple relays for different cooling circuits)

Procedure

1. 1

   Access the relay panel
   Locate the main 12V relay and fuse panel, typically positioned in the front trunk (frunk) area on the driver's side. Remove any cargo covers or trim panels using the trim removal tools. The cooling fan relay is usually in the power distribution module. Remove the relay panel cover by releasing the retaining clips.
2. 2

   Identify the cooling fan relay
   Using the relay diagram on the inside of the panel cover or the service manual, identify the specific cooling fan relay. The EDV 500 typically has separate relays for battery cooling and motor cooling circuits. The relay will be labeled or numbered - verify against the wiring diagram. Note the relay position and orientation before removal.
3. 3

   Document and photograph connections
   Take clear photos of the relay installation, including the orientation of the relay terminals and any adjacent relays. Note any wire color codes visible at the relay socket. This documentation will ensure correct reinstallation.
4. 4

   Remove the cooling fan relay
   Grasp the relay body firmly and pull straight up with steady pressure to remove it from the socket. If the relay is difficult to remove, use a relay puller tool or carefully work needlenose pliers around the base. Avoid rocking the relay side-to-side as this can damage the socket terminals.
5. 5

   Inspect the relay and socket
   Examine the removed relay for signs of overheating (discoloration, melted plastic, burned terminals), corrosion, or physical damage. Inspect the relay socket terminals for corrosion, burn marks, looseness, or bent pins. Check for any melted insulation or heat damage to wiring near the socket.
6. 6

   Test the old relay
   Using a multimeter in continuity mode, test the relay coil resistance between terminals 85 and 86 (typical relay numbering). It should read between 50-120 ohms. Test for continuity between terminals 30 and 87 with the relay energized using a 12V power source applied to terminals 85 and 86. A click should be heard and continuity established when energized. If the relay fails either test, replacement is necessary.
7. 7

   Clean the relay socket
   If the socket shows corrosion or contamination, clean each terminal carefully with a wire brush or spray with electrical contact cleaner. Allow to dry completely. Inspect terminals for proper tension - they should grip firmly but not be bent. If any terminal is damaged, burned, or loose, the entire socket connector must be replaced.
8. 8

   Test the relay circuit
   Reconnect the 12V battery negative terminal temporarily. Turn the vehicle to ON mode (do not start). Use a test light or multimeter to verify that power is present at terminal 30 of the relay socket (constant 12V) and at terminal 85 (ground) or 86 (switched control signal from the cooling system controller). If no power or ground is present, there is a wiring fault that must be diagnosed before replacing the relay.
9. 9

   Disconnect battery for relay installation
   Turn off the vehicle and disconnect the 12V battery negative terminal again. Wait 2 minutes before proceeding with relay installation.
10. 10

    Install the new relay
    Apply a small amount of dielectric grease to each terminal of the new relay if desired for corrosion protection. Verify the new relay matches the old relay in terminal configuration and ratings (check amp rating and voltage rating printed on relay body). Orient the new relay correctly according to your photos and align the terminals with the socket. Press the relay straight down into the socket with firm, even pressure until it seats completely and clicks into place.
11. 11

    Reinstall relay panel cover
    Replace the relay panel cover, ensuring all retaining clips engage properly. Reinstall any trim panels or cargo covers removed during access.
12. 12

    Reconnect battery and initialize system
    Reconnect the 12V battery negative terminal and tighten securely. Close the hood. Enter the vehicle and power on the system. Check for any warning lights or messages on the instrument cluster related to cooling system faults.

Reassembly

1. Ensure the relay is fully seated and locked into the socket with proper terminal alignment
2. Verify all trim panels and covers are securely reinstalled and clips fully engaged
3. Confirm the 12V battery negative terminal is tightened and secure
4. Check that no tools or parts were left in the frunk area before closing the hood

Verification

• With the vehicle in ON mode, monitor the instrument cluster for any cooling system warnings or fault codes
• If available, use a Rivian diagnostic scanner to check for stored fault codes and clear any codes related to the cooling fan circuit
• Allow the vehicle to sit in ON mode for 5-10 minutes to verify the cooling fans activate when thermal management requires them (you may hear the fans run or feel airflow)
• Take a short test drive and monitor coolant temperatures using the vehicle display or diagnostic tool - temperatures should remain in normal range
• After the test drive, verify the cooling fans activate during the post-drive cooling cycle
• Recheck all connections and verify no warning lights are present after the complete drive cycle
• If a diagnostic tool is available, perform a cooling fan relay output test to confirm proper relay operation under command

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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