3-Position IDC Wire-to-Board Connector
The 0.079" (2.00mm) pitch on both the cable side and the board side keeps the footprint compact for a 3-circuit harness.
Unlike a crimp-to-wire connector that requires a separate terminal and a crimp tool, the 2-173983-3 uses an insulation-displacement slot. You press the wire into the slot and the contact edges cut through the insulation to make connection. It saves the cost of loose terminals and a crimp cycle, but the wire must be 26-28 AWG solid or stranded — the slot geometry won't grip a finer or thicker gauge. The yellow housing colour is a visual cue on the line; it's not functional keying.