1993 Ford Probe Two Speed Cooling Fan Circuit Operation - 2.0L & 2.5L

This document is a 'How The Circuit Works' description for the Two Speed Cooling Fan circuit, applicable to vehicles with 2.0L and 2.5L engines (consistent with the uploader's Ford Probe). It explains that battery voltage is always present at the High Speed Cooling Fan Relay contacts through the COOLING FAN Fuse, and that in START or RUN the ENGINE Fuse powers both fan relay coils. When the PCM detects coolant temperature above 97°C (207°F), it grounds circuit 197 (BL/O) on 2.0L engines or circuit 174 (R/W) on 2.5L engines to energize the Low Speed Cooling Fan Relay, running the fan at low speed. If coolant temperature exceeds 108°C (226°F), the PCM grounds the High Speed Cooling Fan Relay coil, switching current to the high speed winding so the fan runs at high speed. On 2.5L vehicles with air conditioning, the High Speed Condenser Fan Relay coil is grounded whenever A/C is on, running the cooling fan continuously at high speed. It references Service Manual Sections 03-03A and 03-03B for diagnostics. Readers can learn the fan control logic, temperature thresholds, relay operation sequence, and the PCM-grounded control circuits and wire colors for each engine.