View Full Version : Radiator fan wiring to a switch help needed
Sidewayz_610
05-08-2014, 08:14 AM
I'm trying to run my isis radiator fan shroud kit for my sr20det to a switch on my dash, not trying to run them to any accessory power or anything. I want the fans to be able to run at anytime .
I wired both fans together at the rad. Ran one wire to chassis ground and the other Into the cabin to a fuse holder and then to a switch. Then back to the positive battery post.
They fans worked for alittle but with a 20amp fuse but eventually popped the fuse. I then put a 30amp in and they worked but then the fans stopped working and the wires going to the switch got very hot (I was using about 14 guage wire)
I'm guessing the wire burnt up somewhere between the battery and switch (haven't had time to check yet with crappy weather)
I read that 30amp needs at least 10 guage wire so I was going to rewire everything with 8 guage. Will that work and be safe? I'm very bad at electrical and just wondering if the electrical gurus will approve before I go by wire and rewire it
Yes. You absolutely need to re-wire it. Or, if wiring is not your niche, have someone else do it for you.
You were overloading the circuit, that's why the fuse popped; the fuse is a failsafe. Then, placing a larger fuse in the circuit, you were still overloading the circuit with the tiny wiring, creating heat, and eventually...fire.
Best bet: Buy a radiator fan controller that has a thermostat built in, then have someone who is comfortable with wiring, wire it in for you...Spend the money; it is worth peace of mind.
Sidewayz_610
05-08-2014, 09:53 AM
Do you think it will be alright with the 30amp fuse and 8 guage wire? I'm trying to keep it simple with no controller if possible but I want it to be safe.
I cant find any specific information online on anyone that ooh red out exact specs of their wiring without going through relays and thermostats etc
Isis did not include any instructions or specs on the fans nor on their website. I researched that most electric rad fans run between 20-40 amps so if the heavy wire won't heat up 30amp fuse should be good.
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cotbu
05-08-2014, 10:06 AM
I personally, prefer ground triggers in the cabin.(kinda like no flammable, caustic, or hot fluids.) Meaning I wouldn't run a toggle switch with a hot source for anything inside the cabin.
I would run the setup you trying to do like this:
fans hot 12v wired to a fuse, then directly to a constant or triggered 12v source. The negative fan wires can then be run to a switch in the cabin then grounded anywhere convenient.
My current fans are wired similar, the switch is mainly there so i can cut power to the fans when I'm working in that area or need to let the engine get warmer than 85c, usually when traveling long distances just a temperature hit at 90c increases my mileage.
2ยข ;)
turbos14
05-10-2014, 02:04 AM
First your engine runs best at a certain temp inside so if you run your fan all the time you will not allow it to do so. Second you are wasting power and horse power via the alternator pushing 25+ amps all the time putting more load on the belt and then to the engine. But if you insist on a switch wire a ground to the switch then the switch to a relay on the control side of the relay under the hood where you wish. Then to a small fuse like 10 amps then to battery. This can be thin wire. Then run the 8 gauge from the battery to the 30 amp fuse then to the switched side of the same relay then to the fans. Then use large 12-10 or 8 gauge wire for ground too to make sure it has a good ground.
The general rule is 5 to 10% more then the item your running for fuse protection. The way I suggest puts the small amp power inside and the large draw fan power under the hood. This the way factory runs them to protect the passenger compartment from things like fire burning melting and so on. If you run the wiring idea mentioned above you still have the big hot wiring running inside up to the switch and defeats the purpose ground side or not.
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S-Nation S13
05-10-2014, 08:31 AM
this is the set up I used slight modifications you may not have maxima/Altima fans but the idea is the same
http://img.tapatalk.com/d/14/05/10/y7y7u7uh.jpg
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S-Nation S13
05-10-2014, 08:33 AM
running pin 86 from the relay would be you best option as a switch as running power into the cabin may have the potential ability to cause a short/fire
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turbos14
05-10-2014, 12:47 PM
Exactly. You best option is run a temp sensor or if it had ac use the ac auxiliary fan control to turn the fans on and off since the ECU controls it based off of temp and vehicle speed. And turn off at higher speed when air flow through the radiator is more then the fans pull. But I would not run the switches power through the same fuse I would run a smaller since a 30amp fuse would take longer to pop if something shorted to ground.
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S-Nation S13
05-10-2014, 04:19 PM
yes each fan will have a separate relay and fuse
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turbos14
05-10-2014, 05:34 PM
The factory wiring diagram for the 240sx and altima will give you a good diagram on how to set up relays and fuses and such
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turbos14
05-10-2014, 05:53 PM
If you ran two switches with the dual fans with separate relays you could also create a hi and low setting low being one hi being both . but the issue with manual fans still stands at if the engine is cooled too much it will not get to proper operating temp which will produce more wear sine the cylinders will not heat up enough to expand and the rings will wear the cylinders. And your car will want to run in cold mode which is not as efficiently and run rich.
The fans running at high road speed would be a waste of horse power to run them and would actually block air flow with the blades spinning instead of free wheeling if they were off allowing more are through unimpeded.
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