Rewiring fans to an on/off switch

ChopstickHero

zoom zoom, eh?
Contributor
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2003 Subaru WRX Wagon, 2000 Miata
Been thinking about this question: has anybody rewired their fans so that they can control it on/off? Ideally it would run just like normal, but when some extra cooling is needed, you can turn it on/off at your will.

Was thinking of this during a short traffic jam, the fan kept going on and off. It would just make sense for it to stay on if it's really that hot.

What would be needed? New fans? relays? switches?

Any wiring geniuses out there (ZapWizard, you still around?) to give some suggestions or comments?
 
Try it, it can't hurt. I had my CRX set up with the ignition as the power source for my fan so every time the car was on the fans would be on. I ran it that way for over 2 yrs with no harm to the fan, a switch would be even easier on the fans.
 
Isn't the fan belt driven? I believe it is, so the task will be a bit more difficult. If it is electrical it's not a problem all you have to do is tap a wire to the positive terminal of the fan and run it to the battery with a ground switch in between. When you leave the switch off the fan will run the way it always does when you turn the switch on the shorter circuit to the power will be open and the fan will turn on when you want it.
 
SNike05 said:
Isn't the fan belt driven? I believe it is, so the task will be a bit more difficult. If it is electrical it's not a problem all you have to do is tap a wire to the positive terminal of the fan and run it to the battery with a ground switch in between. When you leave the switch off the fan will run the way it always does when you turn the switch on the shorter circuit to the power will be open and the fan will turn on when you want it.

I think you've been working on way too many RWDs ;)
 
I know that Brian (BlkZoomZoom) did it, and I think he has a writeup for the procedure floating around.

Search, Grasshopper.
 
Chopstick,

Thought I'd share this with you. I'm looking at doing the same thing. This may also give you some insight as to what is going on in your car. It might be as simple as putting in a cheap 20 dollar part.

http://autospeed.com/cms/article.html?&A=2477

Your fans, or atleast 1 of them, are linked to your Temperature Sensor somewhere in your cooling system. The fans kick on and off based on the amount of voltage that comes out of your sensor.

If your fans are cutting off and on, I can only assume that there is either a fried wire, not-connected wire, or the sensor itself is bad. Either way, 20 bucks to find out is a cheap way of having to re-wire your car with a switch that will have to be replaced every few months or so (if you buy it store bought)

The article i sent you, includes a better explanation, and how to make your own relay switch, or where to find one. Worst case scenario, if you're going to make a home made switch, your best bet is to get an industrial relay switch, and wire your fans to that. Then make a regular switch, that will trip the relay into an on or off position. That way, you're never going to worry about running 12-14 volts into a plastic switch thru 12 gauge wire thru your car.

Hope this helps you out a bit. Good luck :D I'm kinda going thru the same thing myself with my 90 mazda miata. The thing with mine is, the previous owner had a bad sensor, and then hard wired the cooling fan to the blower motor. Now I can't pass emmissions without the fear that it will overheat.

~Doc

Edit:
I just realized that this is 4 years out of relevancy. I should have probably checked that first. Atleast it's good information to have for the next guy who searches.
 
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