Ford Probe DIY High-Speed Fan Trigger Circuit - LM393 Comparator Schematic

This is a hand-drawn electronic schematic sketched in pen (with some traces highlighted in yellow) over a faint printed factory wiring diagram, uploaded to a 1993 Ford Probe gallery. The circuit is built around an LM393n dual comparator IC, with both comparator sections and pin numbers (1-8) drawn out. The left side shows a 'Knock C247 -7' input feeding through resistors R1, R2, and R3 (470 ohms noted) and a capacitor marked '27L 103', with 'JS6 Signal GND' reference connections. The output side uses a resistor network (R4 220, R5 330, R6 ~1.27K, R7, R8, R9, 51K) and drives a TIP120 power transistor whose output is labeled 'High Speed FAN'. An 'ECT' (engine coolant temperature) node is tied into the comparator network and grounded. Labels 'J57' and 'KL' appear on the right side, and VCC supply points are marked in two places. A math note at top reads '690 + 127? / 448 parallel', apparently a parallel-resistance calculation. The document appears to be a DIY circuit for triggering a high-speed cooling fan based on knock/ECT signals, likely designed by the owner for a Ford Probe cooling fan modification. No year, model, or part-number applicability is stated on the document itself.