Pyrotechnic Fuse Inspection

Inspection of the high-voltage pyrotechnic fuses in the battery disconnect system to verify integrity and proper operation of the safety disconnect devices.

Warnings

Tools required

Parts

• High-voltage pyrotechnic fuse assembly × 1 — Use OEM specification - replacement only if defective
• HV connector seals × 2 — Use OEM specification - replace if damaged
• Battery access cover gasket × 1 — Use OEM specification

Preparation

1. Verify technician has completed high-voltage safety training and certification
2. Ensure vehicle is parked on level surface in well-ventilated area away from ignition sources
3. Verify 12V battery is fully charged (low voltage can cause false diagnostic codes)
4. Place high-voltage warning signs around vehicle work area
5. Don high-voltage insulated gloves and verify no holes or damage (perform air test)
6. Set up ESD mat and connect wrist strap to vehicle chassis ground point
7. Connect Rivian diagnostic software and verify no active HV system faults
8. Document initial battery state of charge and HV system status
9. Remove all metal jewelry and conductive items from person

Procedure

1. 1

   Disable high-voltage system
   Using Rivian diagnostic software, initiate the HV system shutdown sequence. Verify all HV contactors are open on diagnostic display. Turn off vehicle completely and remove key card from vehicle interior. Engage parking brake and place wheel chocks.
2. 2

   Disconnect 12V battery
   Open front hood and disconnect negative terminal of 12V battery. Wait 2 minutes for vehicle electronics to power down completely. Disconnect positive terminal and isolate both cables from battery posts. Install lock-out tag on battery.
3. 3

   Access battery pack compartment
   Remove underbody protective panels to access the high-voltage battery compartment. Remove fasteners securing the battery access cover on the underside of the vehicle. Carefully lower the access cover, noting the position of alignment pins. Inspect gasket condition and set aside for reinstallation or replacement.
4. 4

   Verify HV system de-energization
   Wait minimum 15 minutes from HV shutdown for capacitor discharge. Using 1000V-rated multimeter with insulated probes, measure voltage between HV positive and negative bus bars. Voltage must read less than 5V DC. If voltage is higher, wait additional 10 minutes and re-measure. Document voltage reading.
5. 5

   Install manual service disconnect
   Locate the manual service disconnect (MSD) plug on the battery pack. Rotate MSD handle counterclockwise to unlock position. Pull MSD straight out from housing using both hands with steady force. Store MSD in lock-out kit away from vehicle. Verify orange safety indicator is visible in empty MSD socket.
6. 6

   Locate pyrotechnic fuse assemblies
   Identify both pyrotechnic fuse assemblies on the battery pack. The EDV 500 has two fuses: one on the positive high-voltage bus and one integrated with the manual disconnect circuit. They are housed in orange high-voltage protective covers. Note their positions and cable routing before proceeding.
7. 7

   Remove HV connector covers
   Remove the orange protective covers from the pyrotechnic fuse assemblies by releasing the locking tabs. Use panel removal tools if needed to avoid damaging clips. Inspect covers for cracks or damage. Set covers aside in clean area maintaining orientation for reinstallation.
8. 8

   Inspect HV cable connections
   Visually inspect all high-voltage cable connections to the pyrotechnic fuses. Look for discoloration, heat damage, corrosion, or physical damage to cable insulation. Check for proper seating of connectors. Verify orange HV cable identification is intact and legible. Document any abnormalities with photographs.
9. 9

   Inspect pyrotechnic fuse housing
   Examine pyrotechnic fuse housings for cracks, deformation, moisture intrusion, or corrosion. Check that the explosion-proof housing seals are intact. Verify the fuse identification labels are legible and match vehicle documentation. Look for any signs of previous deployment (deformation, burn marks, or broken seals). If any damage is found, fuse must be replaced.
10. 10

    Inspect initiator connector
    Examine the electrical connector for the pyrotechnic initiator circuit. Check for corrosion on pins, damaged connector housing, or compromised seals. Verify connector lock is functioning properly. Do NOT disconnect this connector unless replacement is required. Check wire harness for chafing or damage where it routes to the fuse control module.
11. 11

    Measure circuit resistance
    Using Rivian diagnostic software, perform pyrotechnic fuse circuit resistance test. The system will measure initiator circuit resistance without triggering deployment. Verify readings are within specification (typically 1.8-2.2 ohms). Values outside range indicate faulty initiator or circuit fault. Document all readings.
12. 12

    Perform diagnostic verification
    Execute the complete pyrotechnic fuse system diagnostic test using Rivian software. This checks initiator circuit continuity, isolation resistance, control module communication, and deployment circuit integrity. Verify all tests pass with no fault codes. Review any historical deployment events or fault logs.
13. 13

    Clean and prepare for reassembly
    If inspection is satisfactory, use non-metallic brush to clean any debris from connector areas and mating surfaces. Inspect all connector seals and replace if any damage is noted. Apply a thin coating of dielectric grease to seal surfaces if specified by manufacturer. Ensure no foreign material is present in connector housings.
14. 14

    Reinstall HV protective covers
    Reinstall orange protective covers over pyrotechnic fuse assemblies. Ensure all locking tabs are fully engaged and covers are seated properly. Verify covers are secure and cannot be removed without deliberate tab release. Check that high-voltage warning labels on covers are visible and intact.
15. 15

    Reinstall manual service disconnect
    Insert MSD plug straight into housing socket with steady, firm pressure until fully seated. Rotate MSD handle clockwise to locked position. Verify handle is flush and secure. Orange safety indicator should no longer be visible. Perform gentle pull test to confirm MSD is locked in place.

Reassembly

1. Install new battery access cover gasket if original shows any damage or compression set
2. Align battery access cover with alignment pins and secure with all fasteners in star pattern
3. Reinstall all underbody protective panels and verify all clips and fasteners are secure
4. Reconnect 12V battery: positive terminal first, then negative terminal
5. Remove lock-out tags and safety warning signs from work area
6. Do NOT attempt to start or energize HV system until final verification is complete

Verification

• Connect Rivian diagnostic software and clear any stored fault codes from service disconnect
• Initialize HV system and monitor for proper contactor closure sequence on diagnostic display
• Verify pyrotechnic fuse system shows 'Ready' status with no fault codes
• Check HV system voltage matches expected pack voltage (typically 650-800V depending on state of charge)
• Perform high-voltage isolation resistance test - must exceed 500 ohms/volt
• Test vehicle ready mode and verify all HV systems operate normally
• Perform brief test drive and monitor HV system for any warnings or performance issues
• Document all inspection findings, test results, and any components replaced in vehicle service records
• If any pyrotechnic fuse was replaced, register new component serial number in Rivian fleet management system
• Provide vehicle operator with documentation confirming HV safety system inspection completion

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