The rear High-Voltage Junction Box (HVJB) Gen2 is the main high-voltage distribution node mounted at the rear of the battery pack on early Tesla Model S vehicles. It routes pack energy to the drive unit and on-board charger, houses critical contactors and sensing hardware, and provides properly shielded, sealed transitions for the high-voltage cables. This OEM Gen2 assembly is ideal for collision repairs, pack rebuilds, or replacing a damaged, contaminated, or overheated original HVJB.
Each Gen2 rear HV junction box assembly we offer is an OEM Tesla unit matching part numbers 1021154 / 1021154-02-G / 102115402G. Units are visually inspected by EV technicians for cracked housings, heat-damaged plastic, thread issues, or obvious arcing/tracking. Bus bars and studs are checked for clean mating surfaces, and the enclosure is cleaned so the assembly is ready for integration into your battery pack or vehicle repair.
| Component | Rear High-Voltage Junction Box, Gen2 (HVJB assembly) |
| Part Numbers | 1021154 / 1021154-02-G / 102115402G (superseding and equivalent Gen2 variants) |
| Vehicle Application | 2012–2016 Tesla Model S vehicles using the Gen2 rear HV junction box (verify by VIN and physical style). |
| Location | Mounted at the rear of the high-voltage battery pack, managing pack-to-vehicle HV connections. |
| Primary Functions | High-voltage distribution to drive unit and charger, contactor and precharge control, current / voltage sensing, and cable terminations. |
| Typical Contents | OEM housing with internal bus bars, contactor mounting, and pass-throughs. Exact included hardware (contactors, shunts, sensors) may vary by unit – see product images/notes for specifics. |
| Condition | Cleaned and inspected OEM assembly, free of structural cracks or obvious heat/arc damage, suitable for reuse in service. |
Gruber Motor Company can supply this Gen2 HVJB as a standalone part or integrate it into a complete battery pack rebuild or high-voltage repair in our Phoenix facility. If you are unsure whether your Model S uses a Gen2 junction box or which part number is correct for your pack, send us your VIN and clear photos of the existing assembly and we can confirm compatibility before you order.
Any work on the HV junction box must follow strict high-voltage lockout/tagout procedures. Always fully de-energize the pack, torque HV studs to spec, replace any discolored or heat-damaged hardware, and verify insulation resistance before reinstalling the pack into the vehicle.
Our Tesla specialists routinely repair Model S battery packs and HV junction boxes. For help confirming generation, part numbers, or planning a safe installation, call 623.433.8500 or email our service team with your VIN and detailed photos of your current HVJB.
