Cabin Heater - PTC

This procedure covers the removal and replacement of the PTC (Positive Temperature Coefficient) cabin heater assembly in the 2025 Rivian EDV 500 electric delivery van.

Warnings

Tools required

Parts

• PTC cabin heater assembly × 1 — Use OEM specification
• Coolant line O-rings × 2 — Use OEM specification
• HV connector seal × 1 — Use OEM specification
• Heater mounting grommets × 4 — Use OEM specification

Fluids

• EV Battery/Motor Coolant — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure vehicle has been powered off for minimum 15 minutes
3. Open all doors to ventilate cabin during procedure
4. Place EV service disconnect warning tags on steering wheel and charge port
5. Position coolant drain pan under vehicle near front passenger side
6. Disconnect 12V auxiliary battery negative terminal
7. Verify scan tool is connected and communicating with vehicle

Procedure

1. 1

   Disable high voltage system
   Using the Rivian diagnostic scan tool, navigate to HV Safety menu and select 'Service Mode - HV Disable'. Follow all prompts to safely shut down the high voltage system. Wait for system to display 'HV System Safe' confirmation. Document the shutdown time and wait minimum 15 minutes before proceeding.
2. 2

   Verify high voltage isolation
   Put on high voltage safety gloves. Using the HV safety meter, verify zero voltage at the HV junction box under the hood and at the PTC heater HV connector location behind the dashboard. Document voltage readings (must be 0V DC). If any voltage is detected, do not proceed and re-verify HV system shutdown.
3. 3

   Remove lower dashboard panel
   From passenger side footwell, remove six T25 Torx screws securing the lower dashboard trim panel. Disconnect the courtesy light connector by pressing the tab and pulling straight out. Remove the panel and set aside. This provides access to the heater assembly mounting area.
4. 4

   Drain coolant from heater circuit
   Locate the coolant drain valve on the heater inlet line near the firewall. Attach drain hose to valve and route to drain pan. Open valve by turning counterclockwise. Allow coolant to drain completely (approximately 1.5-2 quarts). Close valve when flow stops. Keep drained coolant clean for reuse if not contaminated.
5. 5

   Disconnect coolant lines from PTC heater
   Using the quick disconnect tool, compress the retaining collar on the inlet coolant line and pull the line straight off the heater fitting. Repeat for the outlet line. Plug both heater ports with the supplied caps to prevent coolant spillage. Have shop towels ready as residual coolant will drain from the lines.
6. 6

   Disconnect HV cable from PTC heater
   Wearing HV safety gloves, locate the orange HV connector on the PTC heater assembly. Press the orange safety lock tab down and slide it toward the connector release position. Squeeze the connector release lever and pull the HV cable straight off. Inspect the connector pins for damage or corrosion. Cover the exposed HV connector on the heater with protective cap.
7. 7

   Disconnect low voltage control connector
   Locate the gray 12-pin low voltage connector on the side of the PTC heater. Press the red locking tab and pull the connector straight back to disconnect. Secure the connector away from the work area to prevent damage.
8. 8

   Remove heater mounting fasteners
   Remove four 10mm bolts securing the PTC heater assembly to the HVAC housing. Two bolts are accessible from the front, two from the top. Support the heater weight while removing the final bolts as the assembly weighs approximately 15 pounds.
9. 9

   Extract PTC heater assembly
   Carefully slide the PTC heater assembly forward and down out of the HVAC housing. Maneuver the assembly through the dashboard opening, being careful not to damage surrounding components or wiring. Remove the unit from the vehicle and place on clean workbench.
10. 10

    Inspect mounting location and clean
    Inspect the HVAC housing mounting surface for cracks, damage, or debris. Clean the mounting surface with a wire brush and vacuum away any debris. Check the heater duct seals in the housing and replace if damaged. Verify the mounting grommets in the housing are in good condition or install new ones.
11. 11

    Prepare new PTC heater assembly
    Remove new PTC heater from packaging. Install new O-rings on both coolant fittings, lubricating lightly with coolant. Remove protective caps from coolant ports and HV connector. Verify the HV connector seal is properly seated. Compare new unit to old unit to verify correct part number and configuration.
12. 12

    Install new PTC heater assembly
    Carefully maneuver the new PTC heater through the dashboard opening and align with the mounting holes in the HVAC housing. Ensure the coolant ports are facing the correct direction and the HV connector is accessible. Insert and hand-thread all four 10mm mounting bolts before tightening. Tighten bolts in a cross pattern to ensure even seating.
13. 13

    Reconnect electrical connectors
    Connect the 12-pin low voltage control connector to the PTC heater until it clicks into place. Verify the red locking tab is fully engaged. Wearing HV safety gloves, align the orange HV connector and push firmly onto the heater until it seats completely. Slide the orange safety lock into the locked position. Tug gently on both connectors to verify secure connection.
14. 14

    Reconnect coolant lines
    Remove the protective caps from the heater coolant ports. Push the inlet coolant line onto the heater fitting until it clicks into place. Repeat for the outlet line. Tug on each line to verify the quick-connect has engaged properly. Verify the retaining collars are in the locked position on both connections.
15. 15

    Refill and bleed coolant system
    Add fresh EV Battery/Motor Coolant to the system through the coolant reservoir until it reaches the MAX line. Using the scan tool, activate the coolant system purge function to remove air from the heater circuit. Monitor coolant level and add as needed. Run purge cycle twice to ensure complete air removal. Check all coolant connections for leaks.
16. 16

    Program and calibrate new heater
    Using the scan tool, navigate to HVAC module and select 'Component Replacement'. Select 'PTC Cabin Heater' and follow prompts to register the new component. Perform the PTC heater calibration routine which will take approximately 5 minutes. Verify the scan tool shows 'Calibration Complete - No Faults'.

Reassembly

1. Reinstall lower dashboard trim panel with six T25 Torx screws, ensuring courtesy light connector is plugged in
2. Reconnect 12V auxiliary battery negative terminal
3. Using scan tool, re-enable high voltage system and exit service mode
4. Start vehicle and verify HV system initializes without faults
5. Remove all service warning tags from vehicle

Verification

• Turn on climate control and set to maximum heat with fan on high speed
• Using scan tool, monitor PTC heater output temperature - should reach 140-160°F within 3 minutes
• Verify hot air is flowing from all dashboard vents
• Check for coolant leaks at heater connections while system is running
• Monitor for any HVAC or HV system fault codes - clear and verify none return
• Verify coolant level in reservoir remains at MAX line after 10 minute run time
• Test heater operation at multiple temperature settings to confirm proper modulation
• Perform final HV safety check - verify HV connector shows no signs of arcing or overheating

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