ok, i had a single fan, and i got a dual fan setup, i want to run a switch to each fan since its cold in the mornings and night and hot enough in the day time to really heat up my engine. so i read all the posts earlier and i cant find any that are intelligable to me that disclude the use of the relays and such, i dont wanna use the temp switch or nothing, i just want a hard line from the switch to the fan. my question is where would i splice to get the juice to the fan, if i cut into the wire going to the starter is that going to keep the juice on after i take the key out? or is it going to run after i turn the car off untill my battery dies or i turn the switch off and forget to turn it on in the morning and boil my radiator....heh.... ok so i splice where to get juice, run that to the switch, the other side of the switch is a wire to the fan, then the second wire of the fan is a wire to a ground...which i can use from the original wire harness to the fan...as long as its the right one and i dont fire up any more wires... and for the juice part, can i wire it straight to the fuse box??? like do i just put a connector on the back of the box, put a fuse in? im lost and my wife keeps whining about all the car parts lying around....
thanks for any help!

 

https://www.thirdgen.org/techbb2/att...postid=1375366

this setup is very safe and very independant of the factory wiring other than splicing into the ground wired on each relay.

 

is there a way to do it without the relay?

 

i would use the factory relays, they can handle the current draw.

 

so youd put the switch in before the relay? i had a single fan application, and im putting in two fans that i want to run independant of the others function, wouldnt i need a second relay? and where are the factory relays by the way??

 

NO. The reason is that unless you find a switch that is capable of a peak current of 20 amps at 12 volts(not your garden variety toggle sw) or at least 40 amps if you want to control both with a single sw. Use MD's diagram. Also the wire size makes it impractical unless you want to wrestle with 10 or 8 guage wire under the dash and try to attach it to a suitable switch. If you insist on doing it that way you must fuse the wire right at the point where you attach it to the battery before it goes to the sw or heads towards the passenger compartment. Even the foglights if so equipped are run by a relay. If you splice to get power, get a tap like the ones they make to go around a battery cable, nothing else in the cars harness is capable of carrying the current. Try it any other way and you'll be popping fuses or ignite the wiring harness. Tap into the battery cable, install a 1 inch or so piece of 8 or 10 AWG wire then IMMEDIATELY install a fuse. If it's going to a common feed wire to two switches and use a 8 AWG wire. Don't try to use a typical inline fuse holder, it will melt over time. Get the large auto fuse, I think it's called a Maxi fuse with a weatherproof holder. Then feed that wire to a switch and back to the fan motors. If it's a common wire to 2 switches then you must tie it to some sort of junction block, tie in 2 feed wires to the switches, IMMEDIATELY fused again from the tie point, with lower value fuses(15A for each sw or fan motor), then to the switches and from the switches out to the fan motors. The wire itself should be something decent like Belden automotive wire or something with a Teflon jacket-not the crap from a home improvement store or Radio Shack. As you can see from all this rambling, using relays is the better way to go and is much safer. Do what you want, but if you try to wire the thing up with a standard toggle switch and used speaker wire you will have a hell of a mess on your hands and possibly need the local FD.

 

gooo, so ill just use a relay...anyways, so since im using a relay now... can i switch the ground? is the possible to do so i can still use the switches??

 

Sure. switch one side on the relay coil exactly like MD's diagram.