This procedure involves removing and replacing the heater core in a 2024 Rivian EDV 500, which requires draining the EV coolant system, removing interior dash components, and accessing the HVAC module.

Warnings

Tools required

Parts

• Heater core assembly × 1 — Use OEM specification
• HVAC module seal kit × 1 — Use OEM specification
• Heater hose O-rings × 2 — Use OEM specification
• Interior trim clips (assorted) × 1 — Use OEM specification

Fluids

• EV Battery/Motor Coolant — 10 qt

Preparation

1. Park vehicle on level surface and allow to cool for minimum 2 hours
2. Disconnect 12V battery negative terminal and wait 10 minutes for system capacitors to discharge
3. Verify vehicle is in service mode using diagnostic software
4. Remove driver and passenger front floor mats and protect interior with seat covers
5. Take photos of all electrical connections before disconnection for reference during reassembly

Procedure

1. 1

   Drain EV coolant system
   Place drain pan under vehicle below coolant drain location near front motor. Locate coolant drain valve on lower coolant line near driver side motor mount. Open drain valve and allow coolant to drain completely into pan. Mark or label coolant for proper disposal. If coolant appears contaminated or discolored, note for service records.
2. 2

   Remove lower dash trim panels
   Remove lower dash panel on passenger side by carefully prying at clip locations with panel tool. Remove side trim panel covering footwell area. Disconnect any electrical connectors for courtesy lights or sensors. Set panels aside in order of removal. Remove knee bolster trim panel below steering column by removing four T25 Torx screws and disconnecting OBD connector.
3. 3

   Disconnect heater core coolant lines
   Locate heater core inlet and outlet lines at firewall bulkhead on passenger side. Use hose clamp pliers to release quick-disconnect fittings on both heater hoses. Have towels ready to catch residual coolant spillage. Once disconnected, cap or plug hoses to prevent further coolant loss. Remove O-rings from bulkhead fittings and inspect for damage.
4. 4

   Remove center console and HVAC controls
   Remove center console trim by releasing clips starting from rear and working forward. Disconnect wireless charging pad connector if equipped. Remove HVAC control panel by removing two T20 Torx screws behind trim and disconnecting electrical connectors. Use multimeter to verify no voltage present at connections before disconnecting.
5. 5

   Access HVAC module mounting
   Remove glove box assembly by releasing side clips and disconnecting damper arm. This provides access to right side of HVAC module. Remove left side lower dash brace by removing four T30 Torx bolts. Disconnect ambient temperature sensor connector near HVAC module inlet.
6. 6

   Disconnect HVAC electrical connections
   Locate and disconnect all electrical connectors from HVAC module including: blend door actuator, mode door actuator, recirculation door actuator, and evaporator temperature sensor. Label each connector with tape or take detailed photos. Use multimeter to verify no voltage present before disconnection.
7. 7

   Remove HVAC module mounting fasteners
   Remove HVAC module mounting bolts: three bolts along top edge (T30 Torx), two bolts at firewall interface (10mm socket), and two side mounting bolts (T30 Torx). Support HVAC module weight while removing final fasteners. Carefully lower module slightly to check for any remaining connections.
8. 8

   Remove HVAC module from vehicle
   Carefully extract HVAC module from dash cavity by tilting and rotating as needed to clear steering column and dash structure. This requires patience and may need slight flexing of ductwork. Once clear, place module on clean protected work surface. Be careful not to damage evaporator or refrigerant lines during removal.
9. 9

   Disassemble HVAC module to access heater core
   With HVAC module on bench, remove module cover by releasing retaining clips around perimeter. Remove foam sealing strips. Disconnect internal wiring harness clips securing actuator wiring. Remove heater core retaining bracket by removing three T20 Torx screws. Carefully slide heater core assembly out of module housing, noting orientation and seal placement.
10. 10

    Install new heater core
    Install new O-rings and seals onto replacement heater core per seal kit instructions. Apply thin coat of coolant to O-rings for lubrication. Carefully slide new heater core into HVAC module housing in same orientation as removed core. Ensure seals are properly seated and core is fully inserted. Install heater core retaining bracket and torque screws finger-tight plus 1/4 turn.
11. 11

    Reassemble HVAC module
    Reconnect internal wiring harness clips. Install foam sealing strips ensuring proper placement. Install module cover and secure all retaining clips around perimeter. Verify all clips are fully engaged and cover is sealed properly to prevent air leaks.
12. 12

    Reinstall HVAC module into vehicle
    Carefully maneuver HVAC module back into dash cavity using reverse of removal process. Align module to mounting points at firewall and dash structure. Install all mounting fasteners finger-tight first, then tighten in sequence: center firewall bolts, top mounting bolts, then side bolts. Ensure module is properly seated before final tightening.
13. 13

    Reconnect all electrical connections
    Reconnect all HVAC electrical connections referencing photos taken during disassembly: blend door actuator, mode door actuator, recirculation door actuator, evaporator temperature sensor, and ambient temperature sensor. Ensure each connector clicks fully into place.
14. 14

    Reconnect heater core coolant lines
    Install new O-rings onto heater core bulkhead fittings with light coat of coolant for lubrication. Connect inlet and outlet coolant lines to bulkhead fittings ensuring quick-disconnects click fully into locked position. Tug on each line to verify secure connection.
15. 15

    Refill and bleed coolant system
    Close coolant drain valve. Add EV Battery/Motor Coolant to system through fill port on coolant reservoir. Fill slowly to allow air to escape. Use vacuum refill tool if available for best results. Connect Rivian diagnostic software and run coolant system bleed procedure. Run heater at maximum temperature and blower at low speed for 10 minutes while monitoring coolant level. Add coolant as needed to maintain proper level. Check for leaks at heater core connections.

Reassembly

1. Reinstall all dash trim panels, knee bolster, and center console in reverse order of removal
2. Ensure all trim clips are properly seated and panels fit flush
3. Reconnect OBD connector and all courtesy light connections
4. Install glove box assembly and verify damper operation
5. Reinstall HVAC control panel and center console trim
6. Reconnect 12V battery negative terminal

Verification

• Start vehicle and verify HVAC system operates normally with no warning lights
• Run heater at maximum temperature and verify hot air output from all vents
• Check coolant level in reservoir and verify it remains stable after temperature stabilization
• Inspect all heater core connections at firewall for coolant leaks
• Use diagnostic software to verify no HVAC fault codes present
• Verify blend door, mode door, and recirculation door actuators respond properly to control inputs
• Test heater output temperature - should reach approximately 130-150°F at vents
• Inspect interior carpet and floor mats for any signs of coolant leakage
• Verify battery thermal management system operates normally using diagnostic software

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