This procedure covers the removal and replacement of the main high-voltage relay (contactor) in the 2022 Rivian EDV 500, which controls power distribution from the battery pack to the drive systems.

Warnings

Tools required

Parts

• Main high-voltage relay assembly × 1 — Use OEM specification
• High-voltage connector seals (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Ensure vehicle is powered off and key fob is at least 20 feet away from vehicle
3. Disconnect 12V negative battery cable and secure away from terminal
4. Wait minimum 10 minutes for high-voltage system capacitor discharge
5. Put on high-voltage insulated gloves rated for 1000V minimum
6. Place high-voltage warning signs around work area
7. Remove front underbody panels to access battery pack service area

Procedure

1. 1

   Access high-voltage junction box
   Remove the cargo area floor panels and locate the high-voltage junction box mounted on the battery pack. Remove the protective cover by removing four Torx fasteners. The main relay is located within this junction box assembly.
2. 2

   Verify system de-energization
   Using the high-voltage multimeter, verify zero voltage at the main relay terminals. Check between positive and negative bus bars, and from each bus bar to vehicle ground. All readings must be 0V DC before proceeding. Document voltage readings.
3. 3

   Disconnect service plug
   Locate the manual service disconnect (MSD) plug on top of the battery pack. Pull the orange service plug straight out and store in a secure location away from the vehicle. This mechanically isolates the battery pack from the high-voltage system.
   ⚠️Never reinstall service plug until all high-voltage work is complete and verified.
4. 4

   Disconnect low-voltage relay control connector
   Locate the 12V control connector on the side of the main relay assembly. Press the locking tab and disconnect the control harness. This connector powers the relay coil from the vehicle control module.
5. 5

   Remove high-voltage cable shield
   Remove the orange high-voltage cable shield covering the main relay connections. This shield is secured with two clips and slides straight off to reveal the high-voltage terminals.
6. 6

   Disconnect positive high-voltage cable
   Using appropriate socket, remove the two bolts securing the positive (red/orange marked) high-voltage cable to the relay. Lift cable terminal straight off the relay post. Inspect terminal for damage or corrosion. Cover exposed terminal with insulating tape.
   ⚠Do not allow high-voltage terminals to contact vehicle chassis or each other.
7. 7

   Disconnect negative high-voltage cable
   Remove the two bolts securing the negative (black marked) high-voltage cable to the opposite side of the relay. Lift cable terminal straight off the relay post. Inspect terminal for damage or corrosion. Cover exposed terminal with insulating tape.
8. 8

   Remove main relay mounting
   Remove the four mounting bolts securing the main relay assembly to the junction box bracket. Note the orientation and position of any grounding straps or washers. Carefully lift the relay assembly out of the junction box.
9. 9

   Inspect and clean connections
   Inspect all high-voltage terminals, mounting surfaces, and the junction box for signs of arcing, heat damage, or corrosion. Clean mounting surfaces and terminals with wire brush or approved contact cleaner. Check that all insulation is intact.
10. 10

    Install new main relay
    Position the new main relay in the junction box bracket, ensuring proper orientation matches the removed component. Install the four mounting bolts and tighten evenly in a cross pattern. Ensure any grounding straps are properly positioned.
11. 11

    Reconnect high-voltage cables
    Remove insulating tape from cable terminals. Connect negative cable first, then positive cable to the new relay posts. Install mounting bolts and tighten securely. Apply thin coat of dielectric grease to exposed metal surfaces if specified by manufacturer. Reinstall orange cable shield.
12. 12

    Reconnect low-voltage control connector
    Reconnect the 12V control connector to the relay assembly. Ensure the locking tab fully engages with an audible click. Verify connector is secure by gently pulling on the harness.
13. 13

    Reinstall protective covers
    Reinstall the high-voltage junction box protective cover and secure with the four Torx fasteners. Ensure all orange high-voltage markings are visible and not obscured.
14. 14

    System verification and testing
    Reconnect the 12V battery. With service plug still removed, connect Rivian diagnostic tool and clear any stored fault codes. Check for proper relay control circuit operation. Power on vehicle and verify no high-voltage faults are present before reinstalling service plug.
    ⚠Do not reinstall service plug if any high-voltage faults are present.
15. 15

    Reinstall service plug and final test
    With vehicle powered off, reinstall the manual service disconnect plug firmly until it clicks into place. Power on vehicle and use diagnostic tool to verify high-voltage system status. Confirm battery voltage is present at drive units. Perform relay function test through diagnostic tool to verify proper operation.

Reassembly

1. Reinstall front underbody panels and torque all fasteners to specification
2. Reinstall cargo area floor panels and trim pieces
3. Remove high-voltage warning signs from work area
4. Ensure no tools or parts are left in high-voltage areas
5. Document relay replacement and serial number in vehicle service records

Verification

• Use diagnostic tool to verify no high-voltage system fault codes are present
• Confirm battery voltage (approximately 400-800V depending on state of charge) is displayed on instrument cluster
• Perform a low-speed test drive and verify normal vehicle operation
• Check that regenerative braking functions properly
• Verify READY indicator illuminates normally when vehicle is powered on
• Scan all vehicle systems and confirm no new fault codes related to high-voltage system

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