Electric Fan

[wrightfox]

i have an electric fan that i want to wire into my pathy...

i have a universal electric fan wiring kit that i picked up from checkers..

i want it wired in properly with a fuse and all..

 

where and how is the best way to wire this fan in??

[jj big shoe]

Where would be behind the radiator.

 

The kit should have instructions, but basically run power from the battery to the fan with a relay in the middle then attach the temp sensor to that relay.

This is how I ran a Taurus fan in mine. Since the Taurus fan is rumored to pull a bunch of amps at startup, I wired it so the temp sensor relay controls a big 80a relay which powers the fan. I also installed an in-cab switch that can shut the whole thing off if I go in deep water, a diode that won't allow the fan to drain power as it freewheels and a lead that turns the fan on with the A/C.

Search around for e-fan or fan wiring. I swear I ran through this in depth before somewhere.

[Kingman]

JJ, where is the wire at that idles the engine up from the AC? I haven't been able to figure it out and I don't want to start cutting wires and burning stuff up. Can you take a picture of it?

[andreus009]

Cool. I've been thinking about doing The E-fan to avoid the radiator drop for the body lift. Plus I'd like some additional cooling at trail speed, mine tends to run a little hot. I've heard you need to upgrade the alternator if you do the electric fan. Is that true? There a lot of different types of electric fans available. Anyone know the minimum CFM fan to use? Thanks in advance. (note: no I haven't searched the subject yet, but plan to in the near future so don't me)

 

Oh yeah, JJ, in your diagram what is the box with the numbers in it?

Edited January 22, 2010 by andreus009

[jj big shoe]

JJ, where is the wire at that idles the engine up from the AC?

The one that will turn the fan on with the A/C?

On my 87 there's two wires for the A/C clutch, one black and one black/pink. I spliced into the solid black one. When the A/C clutch energizes, the 12v kicks the fan circuit on.

Or are you talking about how to keep your RMPs from dropping when you switch the A/C on at idle?

That's a screw adjustment on the passenger side of the throttle body. PM me and I'll send you the "how to".

Oh yeah, JJ, in your diagram what is the box with the numbers in it?

That's the smaller SPDT (single pole, double throw) relay that controls the larger 80a relay. I numbered the posts to identify wiring connections. You could do away with a "wiring kit" and piece this together if it would be less expensive or you've got some of the materials lying around like from some old fog lights or whatever.

Check out the12volt.com. They've got gobs of info on auto electrics. Mostly geared for custom audio, but there's some basic tutorials that are really worth a look if you want to figure out how to wire something up.

I've heard you need to upgrade the alternator if you do the electric fan. Is that true?

I heared that, too. That's partly why I did that first. It might apply mostly to the Taurus fan swap since it's supposed to pull a bunch of amps at start-up, but upgrading to a higher output alt. is a good idea for any additional electrics (fog lights, amps, winch, etc.). Edited January 23, 2010 by jj big shoe

[wrightfox]

wow jj i mean i can do a simple stereo setup.. amp and all that... but this just looks complicated to me.. i just wanted it hooked up to run when the engine was on and the a switch for water like yours.. but all that other stuff is beyond my knowledge.. im more of a visual hands on learner lol but i'll keep looking over it to try to figure it out...

 

i bought the kit. so im guessing that has the relay in it right?

[jj big shoe]

Yeah, the kit should have a relay. Prolly a black cube SPDT one. Depending on the amperage of the fan you might want that relay to power a tougher, larger rated one like in the schematic.

Think of the 12v current flow as water and wires like plumbing pipes.

Ok, starting at the in-cab switch. It's wired to a 12v source that turns on and off with the key.

That 12v runs to the t'stat. The t'stat is simply a switch controlled by heat. If the t'stat is open (contacts are apart), no current flows past it. Once the radiator reaches whatever temp you set, the t'stat will close (contacts are touching) and the 12v will continue to the 1st relay.

A relay is basically a switch that is activated by a low amp current and is used to power a higher amp device. When 12v is applied to post 85, it flows thru a coil inside the relay and out to post 86 (ground). This current flow energizes the magnetic coil inside the relay which closes the contacts between posts 30 and 87. 30 is wired to a constant 12v source (battery).

Now you have 12v coming out of 87, going thru a 25a fuse and powering the big 80a relay, which internally operates the same way the smaller relay does. (you could eliminate the small relay and hook the big one up in its place, but I bought a fan kit that had a small relay with all the wires attached already so I did it this way).

Now the 12v flows thru the large relay to ground which energizes the relay's coil and sends power from the battery to the fan.

Oh, and the A/C wire is there to bypass the power control from the t'stat. Splice into the on/off power lead of the A/C clutch and run it to 85 on the 1st relay. That way the fan will come on whenever the A/C comes on regardless of what the t'stat reads.

[wrightfox]

okay that helped a bit more. still lost but obviously you have to learn somehow right.. but.. as clutch? i dont know what this is.

[jj big shoe]

okay that helped a bit more. still lost but obviously you have to learn somehow right.. but.. as clutch? i dont know what this is.

A/C clutch = air conditioning compressor clutch.

The pulley mounted on the A/C compressor is constantly spinning when the engine is running, just like the power steering pump and the alternator. When its off, the pulley simply freewheels and does not engage the A/C compressor. When you turn the A/C switch on in the truck, it engages the A/C clutch which couples the pulley to the compressor shaft and runs the A/C compressor. You want the fan to come on with the A/C to force air thru the A/C condensor (which is mounted to the engine radiator) which will cool it more efficiently and make your A/C system work better.

Edited January 24, 2010 by jj big shoe

[wrightfox]

haha very nice.. i will def be refering back to this for this wirig.. i also have som kc lights that i want to install.. my standard fog lights dont work.. they were attached to the bumper i bought from the junkyard and when i pluged them in they didnt light replaced them and stillnothing.. im thiking since my connectors were never coverd they may have corroded.. so i am going to attempt to wire my kc's on my front bumper.. going to snag a cruise control switch from a junkyard and hopefully it will work.. that way its a stock switch and will fit with a stock look and be a lit switch?? yeah?

[jj big shoe]

You mean you're going to run your fog lights with a cruise switch? It'll work, sure. You just have to determine which terminals to use. I'd wire them up with a relay (of course you would, JJ) and use the switch to control the relay. You'll get stronger light from them. The longer the wire is, the more voltage you'll lose. If you wire them from the battery to an underhood relay the wire would be much shorter than from the battery to a switch then to the lights.

Check out the12volt.com If you haven't already. Among other things, they explain how relays work and why they are such a good idea in these applications.

[wrightfox]

haha very nice.. gosh i cant wait till i gret taxes.. i found a really nice pathy in our junkyard here.. only one our generation.. beautiful vehicle if it was an manual id almost consider taking off the broke front end and putting everyting into it lol.. i did happen to snap the tail light guards $25. considering taking the doors too cuz they have the exterior panels on the bottom as a guard.. ive always liked the look of those.