thought this would be a good write up as i still see some people suggesting controlling an electric fan with a freaking toggle switch. i did this with all parts i already had, except for the fuse holder. i'm not gonna hook it up unfused. it will turn on at @205* and off at @185*, well within factory operating temps.
on the 89-90 240sx's, there's a switch that's used as an "emergency" fan switch, when it senses the temps of the water coming OUT of the radiator are over 200, it switches on the fan that usually only operates with the A/C. the later sx's also had the fan, but not the same switch.
i did a DE swap into my 90, and i used the radiator from the 92 donor car, which already had this fan on it, so i ditched my mechanical fan, and went looking for a fan controller. one problem. i'm a cheap ass. i wasn't about to drop $40+ on something i could make myself. ok, on to it.
my car already had this, but as it's not used on the DE swap, i made use of it.
![Image]()
i put it in the hose with the switch down, so that if there's an air bubble, the switch will still get a correct reading.
![Image]()
no explanation needed here hopefully
![Image]()
I like trying to solder. i suck at it, but i get the job done. i also don't like crimp butt connectors. they cost more, and as i already stated, i'm a cheap ass. the connections are also more likely to corrode, and where i live, the salt isn't on the road, it's in the air. if you are as bad at soldering as i am, you may end up with something like this
![Image]()
the wire that i added is 12ga. to match the factory size. 12ga. is big enough to run the fan without need for a relay.
the rest is pretty much duhhhh,,,,
hook it all up.
now you don't have to remember to turn your fan on or off. don't give me that B.S. about cool down at the track,,,this will continue to run even with the key off until the coolant in the hose is lower than the temp your thermostat will open anyways.
total cost, about 2cents for solder, and $3 for an inline fuse holder.
on the 89-90 240sx's, there's a switch that's used as an "emergency" fan switch, when it senses the temps of the water coming OUT of the radiator are over 200, it switches on the fan that usually only operates with the A/C. the later sx's also had the fan, but not the same switch.
i did a DE swap into my 90, and i used the radiator from the 92 donor car, which already had this fan on it, so i ditched my mechanical fan, and went looking for a fan controller. one problem. i'm a cheap ass. i wasn't about to drop $40+ on something i could make myself. ok, on to it.
my car already had this, but as it's not used on the DE swap, i made use of it.
i put it in the hose with the switch down, so that if there's an air bubble, the switch will still get a correct reading.
no explanation needed here hopefully
I like trying to solder. i suck at it, but i get the job done. i also don't like crimp butt connectors. they cost more, and as i already stated, i'm a cheap ass. the connections are also more likely to corrode, and where i live, the salt isn't on the road, it's in the air. if you are as bad at soldering as i am, you may end up with something like this
the wire that i added is 12ga. to match the factory size. 12ga. is big enough to run the fan without need for a relay.
the rest is pretty much duhhhh,,,,
hook it all up.
now you don't have to remember to turn your fan on or off. don't give me that B.S. about cool down at the track,,,this will continue to run even with the key off until the coolant in the hose is lower than the temp your thermostat will open anyways.
total cost, about 2cents for solder, and $3 for an inline fuse holder.
