How do you guys with 2 speed electric fans have them wired?

[CJ_]

So I bought a 2 speed electric fan in attempt to battle my high water temps when running my AC in 100º+ weather. I went with a Derale unit which flows 1500cfm at low setting and 2100cfm at high setting, which is the highest I could find for a 14" fan.

As of now, I want to set it up so it always runs in low speed when the engine is running then wire a switch into the cabin so I can switch on high speed when I see my water temp creeping up. Anyone wire a fan like this or have any advice? I want to go this route for the ease of wiring and not having to deal with extra modules and temp sensors.

Also wanting to see what kind of aftermarket or oem switches you guys run in the interior

Heres a link to the fan, any advice is appreciated!:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[vavJETTAw36]

I'd think all youd need is two relays and a switch.

Assuming you want the Fan controller to continue to turn on the fan as normal, Fan hooked up directly to battery switched by relay. The factory fan circuit would switch that relay. The other relay would be switched by your physical switch on the inside of the car and it would switch over the fan setting.

Here is a diagram. Sorry it's hand drawn.




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[CJ_]

Thanks for the drawing, that's pretty much exactly what I had in mind. In that setup, when the switch is turned on, will both the high and low terminals have 12v? Cause the fan requires both wires to have power to enable high mode.

Also the switch would need to have a switched 12v source to it as well correct?

[jaychen]

I live in australia and used to blast my aircon in 100+ weather all the time and it never budged once. Nothing other than to add that the stock system, if working correctly is capable of cooling sufficiently.

[vavJETTAw36]

Thanks for the drawing, that's pretty much exactly what I had in mind. In that setup, when the switch is turned on, will both the high and low terminals have 12v? Cause the fan requires both wires to have power to enable high mode.

Also the switch would need to have a switched 12v source to it as well correct?

Sorry didn't realize they both needed to be together. In that case you will connect the wire going to 30 of the relay to the left directly to the wire that goes to 87a.

Your toggle switch will need to deliver 12v to the relay in order to power its coil. When you power it's coil, you move the internal "flap" from 87a to 87. You can come off of really any circuit for the toggle switch since it will be a very low current task. I'd just come off the 12v of a neighboring switch to make it easier.

I'll adjust the diagram later.


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[rdcyclist]

Which fan are you replacing with the Derale unit? The front one? The one driven by the fan belt through the fan clutch? I'm pretty sure you're not going to improve flow beyond the engine driven fan with an electric unit.

The upside to the EFK is less power taken to drive it along with less weight. Obviously the downside might be hotter running but I haven't seen that.

[CJ_]

I'm replacing the belt driven viscous fan, it simply can't deliver enough air alone to cool the engine when the temps are above 110º. Straight from JHMs website for their EFK:

The JHM EFK completely bypasses the stock mechanical fan pulley and fan without the need to get a new belt. This fan kit eliminates the parasitic engine load cause by the mechanical fan and since it only helps to have it on when you're going under 30mph in traffic, in most cases, it's rarely even used! But when it's needed, you (and your motor) will appreciate the increased cool air flow from the High Flow Fan.

High Flow kits are recommended over Medium Flow kits where summer temperatures are above 90 degrees regularly and for people who may sit in traffic with the A/C on for extended periods of time in such heat.

Which the only time Im really seeing temperature creep is in traffic and driving around town mid-day and temps get into the mid 110s here in Phoenix.

It might be worthwhile mentioning I am also running a FMIC so the stock electric fan was deleted.

I also installed a brand new OEM radiator with the build, so I know thats not the problem

Sorry didn't realize they both needed to be together. In that case you will connect the wire going to 30 of the relay to the left directly to the wire that goes to 87a.

Your toggle switch will need to deliver 12v to the relay in order to power its coil. When you power it's coil, you move the internal "flap" from 87a to 87. You can come off of really any circuit for the toggle switch since it will be a very low current task. I'd just come off the 12v of a neighboring switch to make it easier.

I'll adjust the diagram later.


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Appreciate it!

[vavJETTAw36]

I'm replacing the belt driven viscous fan, it simply can't deliver enough air alone to cool the engine when the temps are above 110º. Straight from JHMs website for their EFK:



Which the only time Im really seeing temperature creep is in traffic and driving around town mid-day and temps get into the mid 110s here in Phoenix.

It might be worthwhile mentioning I am also running a FMIC so the stock electric fan was deleted.

I also installed a brand new OEM radiator with the build, so I know thats not the problem



Appreciate it!

Ok, this is personally how I would wire it. This is to wire it so that the fan control module continues to run the fan when it feels it needs to. You will only have control of setting it high or low and you will not be able to turn it on when you feel like it (remember, fan control module does it)

Also want to note that this does not depict actual wire color. The only accurate color is the EFK fan wiring, brown is high, grey is low.

[CJ_]

It would need to be branched before the first relay like this, correct??

[vavJETTAw36]

Sorry must be tired. Yes, that is perfect. Though it would not cause a problem, connecting to 87a is just redundant.

87a is normally closed meaning 30 and 87a are connected when the coil of the relay is not charged. So it's not needed since we are bypassing it anyways bi connecting before the second relay with grey (low) wire.

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[vavJETTAw36]

Sorry must be tired. Yes, that is perfect. Though it would not cause a problem, connecting to 87a is just redundant.

87a is normally closed meaning 30 and 87a are connected when the coil of the relay is not charged. So it's not needed since we are bypassing it anyways bi connecting before the second relay with grey (low) wire.

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No sorry that is not right. I didnt notice your other changes you made. Let me update the diagram so its clear.

[dannyn424]

i always have mine on the high setting and comes on just like stock settings

[vavJETTAw36]

Here we go:

[CJ_]

Cool thats the configuration I'm going to go with then. Now just need to figure out where to mount a switch in the interior

[vavJETTAw36]

Cool thats the configuration I'm going to go with then. Now just need to figure out where to mount a switch in the interior

I have a solution for you and I dont need to diagram it either



https://www.ecstuning.com/b-genuine-...8d0035775ab98/

You can find it cheaper elsewhere, but just for reference.... But just noticed you have a ESP equipped car so where my car has a blank cover yours has ESP button... You can wire your rear and front fogs together and have one switch and add this funk switch.

[Drehmoment]

Do I read this right that this fan is almost 5 inches thick ? Hayden fans of similar cfm are much slimmer at less than 3 inches.

[CJ_]

I was saving that for something better hahaha but with the front mount, I don't have front fogs for now, so I guess I could just tap into the fog light switch for the fans for the time being, at least till winter rolls around

[CJ_]

Do I read this right that this fan is almost 5 inches thick ? Hayden fans of similar cfm are much slimmer at less than 3 inches.

I believe thats the packaging dimensions, cause the fan is only 14" diameter, I think I read somewhere that its 2 3/4" or something

Edit:

Here you go

Specifications
CFM high/low: 2100/1500
Amp draw high/low: 22/16.2
Width: 14-1/2"
Height: 14-1/2"
Depth: 2-5/8"
Mounting: 8-3/4" x 13-1/4"

[vavJETTAw36]

I was saving that for something better hahaha but with the front mount, I don't have front fogs for now, so I guess I could just tap into the fog light switch for the fans for the time being, at least till winter rolls around

Yes,

Grab yourself a wire tap connector (I like using posi-tap as they are much more reliable) or slide the sheathing back from the wire and solder a wire directly to it (not sure what wire is 12v off of the fog light switch). run this wire to 86 of the relay to the left and that should square away the "physical switch" portion of the solution.

[CJ_]

Sweet, thanks!

On another note, I was able to find the instruction manual for the fan and found this diagram:

Looks like the grey wire may just be a signal wire, and may not need the second relay?

http://derale.com/images/stories/vir...pdfs/18214.pdf

[vavJETTAw36]

Sweet, thanks!

On another note, I was able to find the instruction manual for the fan and found this diagram:

Looks like the grey wire may just be a signal wire, and may not need the second relay?

http://derale.com/images/stories/vir...pdfs/18214.pdf

You might be able to run it that way. As long as low speed does not draw more amperage than the fan (fan clutch, right?) you are replacing. If it doesnt, it will certainly work with only one. Grey IS NOT just a signal wire. Let me adjust my diagram with this second option in mind.

[vavJETTAw36]

You might be able to run it that way. As long as low speed does not draw more amperage than the fan (fan clutch, right?) you are replacing. If it doesnt, it will certainly work with only one. Grey IS NOT just a signal wire. Let me adjust my diagram with this second option in mind.

I recant my last statement. There is no way to do it without two relays. The options in the manual are based on either 1) manual switch, 2) thermostat switch.... You are doing both.

[CJ_]

Does anyone know when this front fan is supposed to come on? I'm in the middle of installing my fan and Im thinking about tapping into the power for it since I have this fan deleted for the FMIC.
(not my car)

[Jism]

That fan turns on by a blue sensor on the left in some coolant line on the bottom. You can hotwire it by wiring pin 1 and 2 together (low) and 3 and 4 for high.

It also turns on when going aftercool when you turned your engine off but the heat is still in there.

[CJ_]

That fan turns on by a blue sensor on the left in some coolant line on the bottom. You can hotwire it by wiring pin 1 and 2 together (low) and 3 and 4 for high.

It also turns on when going aftercool when you turned your engine off but the heat is still in there.

Cool so if I cut the pigtail off of the old fan and splice it in to the new fan, it will essentially run only when the engine gets to a certain temp? Does this fan have anything to do with the AC?

[Jism]

You really should dive into a diagram because i'm not sure when that fan is actually running. You could blow your fancontroller for adding too much of a resistance with more then just 1 fan.

Audi S4 and RS4 uses 3 fans in total from which 1 of them is from the engine itself, 2nd being the Airco-fan (this one is used on both AC and engine heat) and the third one on the front being controlled by a fan controller (right-side bottom IC) and controlled by a small sensor on the left (coolant line, bottom) with 4 wires.

I believe there was different functionality, the front fan only turned on when coolant temp exceeds certain value. Normally any S4 driven car with proper working cooling system is suitable up to 100 degrees, and if not enough you could always turn your heater on.

[vavJETTAw36]

That circuit in question is on a 40a fuse, however, who knows how much the AC condenser fan is individually drawing. I guess you could try it. If the fuse pops you'll have to rewire.


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[MacDaddy]

In arizona especially i would run a low temp thermostat, i wouldnt go so crazy as the engine never got up to temp but it makes a huge difference. Of course i only recommend that provided everything else in thensystem is working properley

[axnjaksn]

So I bought a 2 speed electric fan in attempt to battle my high water temps when running my AC in 100º+ weather. I went with a Derale unit which flows 1500cfm at low setting and 2100cfm at high setting, which is the highest I could find for a 14" fan.

As of now, I want to set it up so it always runs in low speed when the engine is running then wire a switch into the cabin so I can switch on high speed when I see my water temp creeping up. Anyone wire a fan like this or have any advice? I want to go this route for the ease of wiring and not having to deal with extra modules and temp sensors.

Also wanting to see what kind of aftermarket or oem switches you guys run in the interior

Heres a link to the fan, any advice is appreciated!:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

dood, Idk how you feel about it, I have the JHM EFK setup, they have wiring for their relay setup and fan that's pretty straight forward and easy, that's what I used, only problem I ran into, my fan relay over heating and then not working in the stupid HOT socal weather, so I tapped in another relay and power/signal to split the load and the heat, I even ran the wiring up next to my wiper cowl(next to the box that hold the engine control unit) too keep it away from the engine heat, since I ran the second relay, no problems.....also I believe the front fans come on when you turn your AC on or if its up to temp. pm me if you have some questions, id be more than happy to take some pics of mine and send them to you.

[sidewayzgt]

CJ,

Did you end up running your fan like this? If so, what two wires did you tap into on the car in order to get the low temp and high temp switches to activate? Did you fry any relays this way?

Sweet, thanks!

On another note, I was able to find the instruction manual for the fan and found this diagram:

Looks like the grey wire may just be a signal wire, and may not need the second relay?

http://derale.com/images/stories/vir...pdfs/18214.pdf

[vavJETTAw36]

CJ,

Did you end up running your fan like this? If so, what two wires did you tap into on the car in order to get the low temp and high temp switches to activate? Did you fry any relays this way?

That diagram is wrong. Tomorrow I’ll make one for you.

On that diagram you want 85 to be coming from the auxiliary fan switch, 86 from the battery 12v.


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[CJ_]

CJ,

Did you end up running your fan like this? If so, what two wires did you tap into on the car in order to get the low temp and high temp switches to activate? Did you fry any relays this way?

Tbh I don’t remember, I believe I had it on 2 relays and the high speed one was triggered by a switch on the interior. Like the drawing vav posted above.