If you never want the computer/sensors to control the fan, and you want to manually control it all the time, it shouldn't be very hard. It seems that all you would need would be a positive wire, a negative wire, a switch, and maybe a relay. I'm not an electrician, but it seems that you could connect a positive lead to one terminal on the fan, a negative lead to the other terminal, and insert a switch into one of the leads. But then, I'm the kind of guy that sticks his finger into 110 volt outlets just to see what happens, so don't take my word for it.
On the other hand, if you want the computer to control the fan part of the time, and you would over-ride the system manually on occasion, it gets much more complicated. There was a topic on this about a year ago. 99MercMystLS25 described a workable, but "very electronic" technique that would work.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=genmods&Number=33706&PHPSESSID=&fpart=1#Post33706I do know that the motor on those fans (at least on the 95's) draws a lot of amps. I tried to bypass the computer on my fan, and wire a separate thermostat into the system, but I kept shooting 30 amp fuses. I believe the fuse in the fuse box is rated at 60 amps.
--Looking for Commodore stuff (Drives, Units, Amiga, games, etc)If anyone has any of this laying around and wants it gone, lemme know 