A string light engine includes a flexible power cord, a heat sink, an IDC terminal, a PCB, and an LED. The flexible power cord includes an electrical wire and an insulating material for the wire. The heat sink attaches to the power cord. The IDC terminal is inserted through the insulating material and electrically communicates with the wire. The PCB is at least partially received in the heat sink. The PCB includes a first surface having circuitry and a second surface opposite the first surface. The circuitry is in electrical communication with the IDC terminal. The second surface is abutted against a surface of the heat sink so that heat is transferred from the LED into the heat sink. The LED mounts to the first surface of the PCB and is in electrical communication with the circuitry.