The 2nd generation Tesla DC-DC converter takes high-voltage pack power and converts it down to the 12 V electrical system used by lights, modules, relays, pumps, and accessories. When this unit starts to fail, the 12 V battery is no longer charged correctly, leading to random warnings, low-voltage shutdowns, and no-start conditions. This OEM-style replacement for part number 1028665-00-B restores proper 12 V charging on affected Tesla Model S vehicles.
Each 2nd generation DC-DC converter 1028665-00-B we offer is an OEM Tesla unit that has been bench-tested under load by our EV technicians. The converter is energized with a simulated pack voltage and loaded on the 12 V side to confirm stable output, correct regulation, and proper isolation before it leaves our facility. Direct replacement for Tesla Model S 2nd gen DC-DC converter part number 1028665-00-B.
| Part Number | 1028665-00-B (2nd generation DC-DC converter, Tesla Model S) |
| Function | Converts high-voltage pack DC to regulated 12 V DC to support the low-voltage electrical system and charge the 12 V battery. |
| Vehicle Application | Tesla Model S vehicles equipped with DC-DC converter 1028665-00-B. Always confirm by part label or VIN. |
| Electrical | High-voltage DC input from traction battery; regulated 12 V DC output for battery charging and LV loads (OEM Tesla design). |
| Cooling / Housing | Sealed metal housing, designed to mount within the vehicle’s HV electronics area with integrated cooling interface as per OEM configuration. |
| Installation | Bolt-in replacement; requires high-voltage lockout, correct torque on HV and LV connections, and post-install function check. |
| Condition | Cleaned and bench-tested OEM unit, inspected for connector damage, corrosion, or heat-related defects. |
Gruber Motor Company can supply this DC-DC converter as a stand-alone part or install it as part of a larger high-voltage / low-voltage diagnostic and repair package in our Phoenix facility. If you’re unsure whether your Model S uses 1028665-00-B, contact us with your VIN and a photo of the existing converter and we can confirm fitment.
Any time you replace a DC-DC converter, replace or test the 12 V battery and inspect all major grounds and high-current LV connections. A weak 12 V battery or poor connections can shorten the life of the new converter and cause recurring 12 V system warnings.
Our Tesla specialists diagnose DC-DC converter and 12 V charging issues every day. For help confirming part numbers, interpreting fault codes, or planning an installation, call 623.433.8500 or email our service team with your VIN and photos of your existing converter.
