Installing a Fan Switch

There has been a lot of discussion about the Coolant fan temperature switch. Your Fiero coolant fan is turned on & off by the inputs from the coolant temperature sensor, speed sensor & the A/C system. Battery voltage is supplied at all times to the coolant fan relay. The fan (or fans incl the rear fans in those so equipped) is energized by merely providing a ground. This is done when you put the A/C in MAX. NORM, or B/L, or the A/C High pressure cut out switch. When the coolant temperature exceeds 235F. The coolant temperature switch closes, and provides the ground to the relay coil to be energized. If you want to switch your coolant fan on whenever you want, all you have to do is manually provide the ground through a switch. Find the main wiring junction block on the front firewall above and forward of the brake pedal (inside the car!) Find the dark green and white stripe wire in plug F9 (4th up from the bottom on the left side) and splice into it through a switch, to ground. (Do not cut the green/white wire). When the switch is turned on, with the ignition on, this will ground the relay, which activates the fan in the same way the coolant temp switch & A/C switch does. I located a black rocker switch in the plate where the defogger switch normally would be, but you can find any good spot. No more worries about creeping temps in hot traffic! The real question is why do this at all? The Fiero was designed to run at these temps, and when it gets hot the fan comes on! (supposed to!). Maybe all you need is a new coolant fan sensor!, especially if the fan(s) come on when you put the A/C on.

From: Paul Vargyas

A manual switch one listmember installed in a Ford Escord

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