92RS_T-Top

How do you wire in a toggle switch to run your electric fan?

After doing my motor swap the electric fan dosnt want to kick in, at all, so i plan on just hard wiring it to a toggle switch mounted above the light switch, seeing as how i already have a toggle switch there that runs to nothing at all. Any help would be appresheated id hate to melt a nice toggle switch melt down and cause a electrical fire in my car that i just got back to running.


Side note, the fan DOSE work when jumper wires where ran to the battery, and i know witch wire is the power and witch is the ground, just need to know how to wire up the toggle switch so i dont have a melt down.

Thanks guys

camaronewbie

You need to use a relay, so that you don't draw too many amps through the toggle.

I highly recommend using a seperate fan controller, I use a Flex-a-lite, and it's the best $100 I ever spent.

But if you just want a toggle for now, go to any auto parts store and get a relay, about $8, then follow this:



I'm assuming it's a lighted toggle? So, you need 12v+ from fuse block in to toggle, and a ground for the toggle (in order for the light to illuminate), then a 12v+ wire out of toggle - run this wire out to under the hood, and mount relay underhood. You can crimp on a 1/4inch male spade terminal to the wire end going to fuse box, and stick it in an empty slot you'll see marked IGN with a small arrow to it - that will supply 12v+ only when key is on so you don't accidentally leave fan on overnight.

Then:

85 = 12v+ wire from toggle (any small like 18 ga wire fine)
86 = ground (again, any small like 18 gauge fine)
87a = NOT USED (some relays have this, some not - not needed anyway)
87 = 12v+ out to fan (fan positive wire should be black with red stripe) and use nice 10-12gauge wire here
30 = 12v+ from battery (either from battery, or from starter where the pos battery cable connects, or from the power distribution center beside radiator) you want nice 10-12gauge wire here (thicker)

So - with key on, the toggle gets 12v+ ... when you flip the toggle on, the 12v+ is sent to the relay, activating it, and connecting 30 to 87, thus giving your fan 12v+ directly from battery. Saves running high amps to a low amp rated toggle.

No need for any fuse anywhere with this - relay is rated at 30 amps and will burn up if more than 30 amps is drawn through it, and the toggle switch wire from fuse block won't even draw 5 amps for the light and to activate the relay (relay only needs 200 milliamps to activate, light in toggle might draw 4 amps).

whatever84

Yep... ^^^What he said!!

Mark.

92RS_T-Top

Thanks man, that is exactly what i was wanting to do! I already bought a 30amp toggle switch, with the red l.e.d. so i can make shure i shut it off when i was leaveing the car... But with the relay can I leave the fan off till the car warms up to normal running temp? I only ask because my car is VERY cold natured and wont run worth a dang untill it gets up to around 140, so leaving the fan off till it hits 180ish is what ive been doing to warm the car up for the drive home. The way ive been terning the fan on sens the motor swap is by terning the AC on.... witch is weird as i have no ac wires hooked up lol.

Thanks again man, i'll go get that relay friday at the auto parts store, and seeing as how i have to readjust my rockers again for the 3rd time (they keep losing, up new heads i hear do that till they seat) so i'll already be under the hood working on it.

camaronewbie

Yep - fan won't come on until you turn on the switch. And it'll turn off when you turn off the switch.

And if you run the toggle wire to that IGN slot in the fuse panel, the fan should turn off when the key is off, so it won't stay running all night in case you forget.

one92rs

iTrader: (5)

i also use a flexalite controller. comes with everything needed. it has provisions to have extra toggle switches installed. two switches. one all on and the other all off. and i wired in a light so i would know when it comes on.
bottom right corner is the switches and the light.

camaronewbie

Yep - me too - Flex-a-lite controller rocks! I have my switches in the ashtray hidden (4 of them, only using 2 at the moment. And I wired in a LED in the upper left instrument panel.

I spy a 4th gen steering wheel there!

one92rs

iTrader: (5)

ssshhhhhhh on 4thgen. it was free.

hey can you take or show me a pic of the light you did.

92RS_T-Top

No joke i'd like to see how it looks.

My car is back in the barn the heater core went out and ive been working on that all weekend and monday, orileys gave me the wrong heater core and had to order a new one in, so ive been workin on this fan set up and where to mount the new toggle.

camaronewbie

Sorry - don't have a pic of the LEDs I put in the dash, and it's raining like mad today so I can't get one. But, looking at your instrument cluster, the very upper left corner, there is a place with nothing in it, about 1in tall and maybe 3 inches long. I put 3 LED's there, just simple small LED lights from Radio Shack. I just spliced in a positive wire from my switch to the LED positive, and wired a ground for the LED - so when the switch is on, the LED lights up.

I can show you the ashtray switches I installed, one of which is for my manual on fan function:

TraviZ

iTrader: (2)

that pic is cool, i wanted to do the exact same thing, just never knew which switches would have the clearance to allow the ashtray cover to close.
I need to hide my line lock switch

camaronewbie

Those are off the shelf from autozone. www.wiringproducts.com has even smaller ones now, with more LED colors available than autozone's switches - might could squeeze 5 of those smaller ones in the ashtray.

silverado638

Hey to the guys that run the flex a lite fan controller. Where did you get it. I'm lookin on Summit and there's a bunch of different options anywhere from $30 up to around $200 and I just wanted to make sure i'm getting the right thing for a single fan set-up

RaGiN Z

I'm not quite sure why you would run a toggle switch, have the fan just come on with the ignition.

I have the taurus fan, low starts with the car, and high comes on at 180* using a controller I got at pep boys for like $40. I ran everything off a solenoid that has 100% duty cycle and then off a pair of relays which turns off the low when high comes on

92RS_T-Top

The fan comeing on when the key is on is what im trying to avoid, for the simple fact that i would like to listen to my radio from time to time while working on the car without the fan being on. As my car dosnt have the accessory spot... SO running the fan off toggle helps, that and it being a carbed car now with no choke and being very cold natured i need it to warm up faster then normal.

J91

Man you guys really complicate the hell out of things. Hardwire the stock fan or fans w/ a constant 12volt source to each fan relay, then run a toggle for each fan on the ground to complete the circuit....

BlackenedBird

iTrader: (5)

y84pauloflondon

It may seem complicated for some, but its the right/proper way of doing it!!!

J91

It's not complicated at all, just unnecessary. I have been running my fans that way for years, and I didn't spend any $$ except for two toggles.

irockid86

my car was set up with a grounded toggle when I bought it. Just connect a toggle switch to the green wire with white stripes coming off of the relays. Is this dangerous in any way? If not I'd say its right/proper, but I don't have a lot of experience with electronics.

J91

Not a thing wrong w/it as long as relays are in place. A DC circuit is just what it says direct current, it is either complete (on) or not (off). The realy will not turn on (close) and pass current until the circuit is complete.

camaronewbie

Yep - using a switch to the small green/white fan switch wire off the relay is fine - that's low amps. I just don't like running high amperage wires through the firewall - I'd rather have the fire potential on the right side of the "firewall" - if you get my drift.

The relay setup is assuming that the factory relay system doesn't work (bad connectors, bad wiring, bad mouse ate something, etc.), or that there never was an original electric fan but you've swapped from mechanical fan to electric.

I guess running a toggle for switching the ground on/off on the fan could work - but you still have high amps on the fan ground wire (otherwise the factory would have used a 18ga wire rather than a 10ga wire). Just because it's a ground doesn't mean it doesn't draw amperage - remember you are completing a circuit - a circuit is by definition a "circle" of current. If there's 30 amps on the positive side of the circuit, there needs to be a ground wire large enough to handle 30 amps of electricity on the ground side - when the "circle" is complete, 30 amps runs through the entire circuit (minus what the fan draws out).

So, in theory anyway - you'd still need to run a wire capable of holding 30 amps to the toggle switch, AND have a toggle capable of handling 30 amps (most on-the-shelf toggles these days are chinese, and lucky to actually handle 10 amps). Otherwise, what happens if the fan doesn't draw the entire 30 amps out? It has to complete the circle, thus it runs on the ground side (if that makes sense). It's like Nascar - the track is made to hold 45 cars at once - not all 45 cars are always on the track (some crashed, some pitted), but the entire track has to be able to handle that many cars safely. (OK, enough with my weird analogies).

This is why you have such a huge ground wire for your sub amp - otherwise any old 20ga wire would suffice - but most folks use a 1ga wire for positive, and a 4ga wire for ground. And folks with big monster stereo systems and amps, they run additional huge 1ga grounds from battery neg post to car body, so that the amps can get enough grounding off the body back at the rear of the car.

You have to think of the complete circuit, not just the positive side.

J91

Good theory, you are forgetting one thing though, the fan motor itself uses up power. I checked the amperage on the ground side at the switch, measured 5.5-6.5 amps, now if a fan quit working or on startup and stop the ground is gonna see more amperage, how much? I dunno.

remltr

iTrader: (4)

If you're gonna do all of this wiring and you have the relay, just get a breaker and a sending unit to turn on the fan automatically? I just did a 305 tbi to 383 carbed swap and my fan works just fine. All you need is relay, breaker and sending unit maybe 40-60 bucks and no "ghetto" toggle. Try Summit, PN# SUM-890015 $45!

irock88

If a fan stops working you will not see an increase in amperage as the motor is not working so its not drawing current,on start up you will see a momentary increase in current(amperage)then it will drop back to its normal value while running. Just curious as to how the ground will see more amperage while the motor isnt running or its stopped.

camaronewbie

Hell, I don't know! I'm no electronics wiz! I just assume that if a large ground wire wasn't needed for the fan, then it wouldn't have one.

I have seen large stereo amp folks made extra ground connections from battery to car (or motor to car) and they say it helps (maybe not necessary, but it helps). So you must have to match the gauge of the ground to the gauge of the pos wire to some degree.

J91

That would be a very momentary increase, not a constant, you are probably talking hundreths of a second for a small spike, and then gone...

y84pauloflondon

Both my friend and I found out how important it is to have a good quality relay. We both were using a relay from Standard Electronics, both began melting down within a 1 1/2 yrs of use.

GM basically had the same problem with some of there relays recently. So anyone with cooling/overheating, fan issues that went in to a dealer were given a HD relay. This HD relay is now used in my 87 GTA and my buddy's 91 Syclone, 3 yrs and going, no problems....

GM # 12177235 (Omron relay)

RaGiN Z

wrong, I have it wired to turn on with the car, not turn on with the key in my 83. There is a wire on the passenger side, I believe its pink that only comes on with ignition. You wire that to the relay or solenoid, that controls everything, I have that trigger the low fan and water pump but it doesn't come on when I turn the key to accessory. I don't have a choke either on my 750 DP, I don't find that I have to sit for any longer than I did before. Your thermostat is still closed and therefore you shouldn't have to be hindered by it. The only thing I could see being a problem is the battery draw when you are trying to start the car but I just have a good battery with high CCA and you should be good to go.

RaGiN Z

that and you could always run your relays in parallel to split the load, which is what I did for the high side.