Curtis 1264‑5403 is a 48 V, 400 A brushed DC motor controller used in heavy‑duty electric vehicles such as golf carts and utility transporters. Common failure modes for this class include overheating of the power MOSFET array or IGBT modules, blown internal fuses, degradation of the gate driver circuitry, insulation breakdown between windings, and mechanical wear on the speed sensor contacts. First‑check diagnostics: verify that the 48 V supply is within spec and the current rating is not exceeded; inspect all fuses and replace any blown ones; visually examine the MOSFETs for burn marks or discoloration and test the gate driver outputs with a multimeter or oscilloscope; finally, review any stored error codes via the controller’s diagnostic interface.[oss-gpt-20b]