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
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
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
especially if the fan(s) come on when you put the A/C on.