I have a simple way to wire fans to factory relay

[chris1212]

'[IF SOMEONE SEES A FLAW IN THIS PLEASE TELL ME BEFORE I MESS SOMETHING UP]
Ok the factory radiator fan relay has an normally open set of contacts just like a normal relay. So im thinking those contacts close when your temp gauge goes up. #3 on your relay will energize when the temp moves up. So look under your relay at the plugs and find #3, its printed 1,2,3 and 5. Just hook the power wire from your fans to #3 on the '[HI RADIATOR FAN RELAY] and the second fan wire to a good ground or battery ground. this worked for me and now my fans come on and go off like they should. No after market relay was needed only some wire..If you notice #3 is running to your factory fan plug so you can also tap in at that spot.
I also saw on here some where that your fan should run while your AC is on, witch is true for a real air condition condensor on your house. if not the compressor gets hot, head psi goes up and the unit shuts down. So with that being said, just run a second power wire #3 on your AC relay. I tried this also and my fans come on when the AC button is on along with the inside blower control knob..I also double checked to make sure the fans do not come on in heat mode with the inside control knob. So the fans only work with the AC button+ blower control knob when dealing with the heat and air deal...all of this deletes my purpose of having my aftermarket temp sensor pen hooked to my radiator and making my fans come on when it feels heat. im always having to adjust the controls according to the weather. and most importantly when I park my car the under the hood temp goes up and the fans kept coming on minutes after to cool off everything. that pulls on the battery.

[2_Liter_Turbo]

The factory temp gauge is not very good, and so it's misleading. The factory e-fan relay switches on at around 205°F if I remember correctly, which is getting real hot for a 240 (especially SRs). You want them to run at 180°F +/- 10°F which is what the thermostat is set at. While a lot of people have done this mod in the past, it's not good for the motor to be running so hot at all times. It wears it out faster than normal. Just thought I'd let you know.

If you want e-fans, a good solution (and cheap) is to wire up some altima fans using factory blue 30 amp relays and an aftermarket thermostat of some kind. You can make it real clean, there is typically extra room for the relays in the box underneath the air filter box.

[chris1212]

Thanks for the info..I was just informed this on the ka engine form as well. i've been running my autozone temp probe, stuck to my radiator. it seems to be working fine..Like you said , I've noticed sometimes it gets really hot before turnning the fans on.It takes a while to find a sweet spot so the fans don't run as much. and I think I've got it..

[2_Liter_Turbo]

No problem, didn't want you to find out the hard way