Pyrotechnic Fuse Inspection

Inspection of the high-voltage pyrotechnic fuse assembly for damage, corrosion, or degradation. This safety-critical component disconnects the battery pack during a collision or system fault.

Warnings

Tools required

Parts

• High-voltage connector seals (if damaged) × 2 — Use OEM specification
• Pyrotechnic fuse assembly (if replacement needed) × 1 — Use OEM specification
• Cover gasket (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place safety cones or barriers around vehicle to prevent unauthorized access during high-voltage work
3. Ensure ignition is OFF and key fob is at least 15 feet away from vehicle
4. Open hood and locate 12V battery in front compartment
5. Disconnect 12V negative battery cable and wait 2 minutes
6. Disconnect 12V positive battery cable and insulate terminal
7. Don high-voltage insulated gloves and verify no damage to gloves
8. Connect diagnostic scan tool and verify no active drive cycle

Procedure

1. 1

   Access high-voltage battery compartment
   Remove rear cargo floor cover and fold down rear seats. Remove cargo floor panel fasteners and lift panel to access battery service disconnect area. Remove trim panels along left side of cargo area to expose high-voltage service disconnect cover.
2. 2

   Remove high-voltage service disconnect cover
   Locate the orange high-voltage service disconnect cover on top of battery pack. Remove cover screws in sequence and carefully lift cover. Inspect cover gasket for damage and replace if compromised.
   ⚠Cover screws secure seal that prevents moisture intrusion. Do not overtighten during reassembly.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
3. 3

   Remove high-voltage service disconnect
   Grasp the orange service disconnect handle and pull straight up with firm, steady pressure until disconnect releases from connector. Place disconnect on insulated surface. Verify disconnect indicator shows DISCONNECTED position.
   ⚠️Do not twist or rock disconnect during removal. Pull only in vertical direction to avoid connector damage.
4. 4

   Wait for high-voltage system discharge
   Wait minimum 10 minutes to allow high-voltage bus capacitors to fully discharge. Use diagnostic scan tool to verify high-voltage bus voltage is below 5V DC. Do not proceed until voltage is confirmed safe.
   ⚠️Residual voltage can remain in system even after disconnect removal. Always verify with meter before proceeding.
5. 5

   Access pyrotechnic fuse location
   The pyrotechnic fuse is located inside the battery pack near the service disconnect area. Remove battery pack access cover by removing mounting bolts. Carefully lift cover to expose fuse assembly and high-voltage bus connections.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
6. 6

   Disconnect high-voltage cables from pyrotechnic fuse
   Using insulated tools only, remove high-voltage connector bolts from both sides of pyrotechnic fuse assembly. Carefully pull connectors straight off terminals. Inspect connector seals and replace if damaged, cracked, or compressed.
   ⚠️Even with system de-energized, treat all orange cables as live. Never allow connectors to contact chassis or each other.
   Torque spec

   Connector Bolts7 Nm (5 lb-ft)
7. 7

   Remove pyrotechnic fuse bracket assembly
   Remove bracket bolts securing pyrotechnic fuse assembly to battery pack structure. Carefully lift fuse assembly with bracket from mounting location. Support assembly weight to prevent cable strain.
   Torque spec

   Bracket Bolts20 Nm (15 lb-ft)
8. 8

   Inspect pyrotechnic fuse physical condition
   Visually inspect fuse body for cracks, burns, discoloration, or physical damage. Check for signs of moisture intrusion or corrosion on fuse terminals. Inspect fuse mounting bracket for cracks or deformation. Any damage requires fuse replacement.
   ⚠️A deployed or damaged pyrotechnic fuse MUST be replaced. Never attempt to test or reuse a questionable fuse.
9. 9

   Check fuse electrical connections
   Inspect fuse terminal connections for corrosion, pitting, or discoloration. Verify terminals are clean and free of oxidation. Check continuity across fuse terminals using multimeter (should show low resistance, typically under 0.1 ohms). Record resistance value for documentation.
10. 10

    Inspect pyrotechnic initiator circuit
    Locate the two small initiator wire connections on fuse assembly. Visually inspect wiring and connector for damage. DO NOT measure voltage or resistance on initiator circuit as this could deploy the fuse. Verify connector is clean and properly seated only.
    ⚠️Never apply voltage or perform resistance testing on initiator wires. This can cause unintended deployment.
11. 11

    Check fuse module mounting hardware
    Inspect module mounting bolts and bracket for proper torque and condition. Check for loose hardware, damaged threads, or missing fasteners. Verify bracket is not bent or cracked from previous service.
    Torque spec

    Module Mounting Bolts8 Nm (6 lb-ft)
12. 12

    Reinstall pyrotechnic fuse assembly
    If inspection passed, carefully position fuse assembly back into mounting location. Install and torque bracket bolts to specification in cross pattern. Ensure fuse body is properly seated and aligned with high-voltage bus connections.
    Torque spec

    Bracket Bolts20 Nm (15 lb-ft)
13. 13

    Reconnect high-voltage cables
    Apply dielectric grease to connector seals if specified by service manual. Align high-voltage connectors with fuse terminals and push straight on until fully seated. Install high-voltage connector bolts and torque to specification. Verify connectors are secure and properly oriented.
    ⚠Ensure connector orientation is correct before tightening. Reversed polarity can damage battery management system.
    Torque spec

    Connector Bolts7 Nm (5 lb-ft)
14. 14

    Reinstall battery pack access cover and service disconnect
    Install battery pack access cover and torque mounting bolts to specification. Align service disconnect plug with receptacle and push straight down until fully seated with positive click. Verify disconnect indicator shows CONNECTED position. Install service disconnect cover with new gasket if needed and torque cover screws to specification.
    Torque spec

    Module Mounting Bolts8 Nm (6 lb-ft)

    Cover Screws11 Nm (8 lb-ft)
15. 15

    Restore vehicle electrical systems
    Reconnect 12V positive battery cable first, then negative cable. Use diagnostic scan tool to clear high-voltage disconnect DTCs and verify no new fault codes. Command high-voltage system enable and verify battery pack voltage rises to normal operating range (approximately 350-400V). Reinstall all cargo area trim panels and test vehicle readiness.

Reassembly

1. Verify all high-voltage connector bolts are torqued to specification and safety-locked if applicable
2. Ensure service disconnect cover gasket is properly seated to prevent moisture intrusion
3. Confirm all cargo area trim panels are securely fastened and floor cover is properly installed
4. Remove high-voltage safety equipment and store properly for next use

Verification

• Use scan tool to verify no active high-voltage system DTCs are present
• Confirm READY indicator illuminates on instrument cluster when vehicle is powered on
• Verify high-voltage battery voltage displays normal range (350-400V) on scan tool
• Test vehicle movement in forward and reverse to confirm drive system functionality
• Perform visual inspection of pyrotechnic fuse area for proper reassembly with no loose parts or tools
• Document inspection findings including fuse resistance measurement and any abnormal observations in service records

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