The Thermo King 2C26664G01 is the base controller for V‑280 truck‑mounted refrigeration units, managing temperature setpoints and compressor cycling via a printed circuit board with integrated power regulation and signal conditioning. Common failure points in this class include burnt or tripped MOSFETs on the power stage, degraded capacitors on the voltage regulator, and shorted or open I/O traces to the temperature sensor and relay driver outputs. Begin troubleshooting by verifying 48 V DC supply continuity and proper voltage levels at the board’s input pins; inspect for visual signs of component damage such as bulging caps or scorch marks. Next, check all signal lines (temperature sensor, compressor relay) with a multimeter or oscilloscope for correct logic levels and continuity, then review any stored error codes via the unit’s diagnostic interface before proceeding to component replacement.[oss-gpt-20b]