No pictures.... yet, but see if you guys can solve this one.

This is a s4 JDM 13bt and the coolant neck above the thermostat has what looks stock; two water temperature sensors?

The lower one connects to the harness but the other I don't know about, it has a single male clip electrical connector on it.

I'm trying to install an electric fan on my car and if this is some type of temperature sensor I'd like to wire it up, but I need the info first. If no one knows off hand I'll work on getting a pic posted.

Thanks!

 

That's an extra sensor the TurboII came with, it's for the extra electric fan that the radiator uses. THe connector is on the engine harness.

 

^^^^^^^ Zackery!

 

There is only one stock temp sensor (switch actually) on the S4 thermostat cover, not two, and it's for the auxiliary electric fan fitted to some models. The second one is probably aftermarket. Got a pic?

 

will post pic soon as i get off work today, but if it is for an auxilary fan, can i use aaroncakes wiring diagram and run my fan off it?

 

IMO it's not suitable because it triggers too high (97degC/207degF). As well as running when the A/C is on, the e-fan is used to assist the main fan if necessary, hence the high trigger temp.

 

okay here is the pic I was promising. On the coolant neck close to my hand is the exposed connector, that thing what we're thinking it is?

And and and, if that is too high a temperature setting. Would it concievably work to screw in a lower temperature activated temperature sensor aftermarket?

And if so or what not how would that work in wiring the fan.

 

It's still the water temp switch for the auxillary fan. The item with red around it way below your hand.

 

yeah but can it be switched out with an aftermarket sensor to run the fan?

 

and is it me or does it look like my cap is leaking coolant over the engine?

 

If you can find a sensor/switch with the same threads. But you could work around that with an adapter if it'll fit down into the flow of water.

 

Thanks for your help Hailers!

I'm not an electrician at all but since this is the only fan I'm running and I don't want to find out the hard way I did it wrong, could you compare what I would need to do with that temperature sensor with this wiring diagram from aaroncake and tell me what I need to do to make it work? I've completed the rest of the circuit minus the coolant temperature sensor.

Thanks again!

 

You said there were two sensors on the neck...

 

if its your only fan and your truly concerned about keeping the car cool, why not hard wire to run when the key is on? or run with a switch?

Otherwise that fan will be kicking in and out in and out in and out with the thermostat, which really isn't a problem, it just drains more amps. But the stock clutch fan isn't designed to come on at a certain temperature, why rig it otherwise? Also with a switch that is powered directly off the battery, on can leave the fan running for cool down after some fun runs

 

The other temperature sensor connects to the harness for what I'm assuming is the WTS gauge.

And I've read alot of people's opinions on when to run an E-fan. I think this is the best set up for my application.

I had a Ford Probe GT that had some electrical issues, one of which was fan related so we hard wired a switch to the passenger compartment. It was pretty ghetto fabulous and sometimes I'd forget to turn it on so I'd rather eliminate myself from the equation.

I'd like the car's cooling system to police itself as if it was stock, IE, cooling itself when needed.

Plus turbo's run hot and mine is no exception, I don't mind the extra pull on the battery after the car is off since it's doing it's job anyway. And also I don't want it running all the time as I've heard warnings against running the engine too cold. Most of the time driving places doesn't allow me the time to let the rex warm up for ten minutes or so before driving it.

I do try and let it warm up a bit before driving, but it's like 2 to 3 minutes. And also never boost when the engine is still cool..

If I run into several dead batteries as a result (Pending succesful wiring of course) of the fan running with the car off. Then I'll look into the added ignition control as I have the other wiring diagram as well.

I'd like to test this set up on my car first though as a preference.

 

Because that's dumb. Fans are only required at low speed and when stopped. Running it constantly is just a huge unnecessary load on the electrical system, will dramatically shorten the fan's life, and will not make the engine run cooler.

Even dumber. At least if it runs all the time you can't forget to turn it on and cook your engine.

That's how it's supposed to work! It's exactly how every OEM electric fan system operates and and is the way every custom set-up should work too.

BS.

Yes it is actually.

You need to do a lot more learning on how cooling systems work...

 

Thanks for paying attention to the details NZ

But I still need confirmation that all I have to do to make that wiring diagram complete is plug the fan into the TS? If I was using the engine as the ground? Like I said the relay and battery connections are all complete, just not the WTS. But I need to know how that sucker works!

Many thanks for you guys saving my ***.

*sniff* you know.. I love you guys..

 

ideas?

 

The S4's e-fan temp switch is a normally-closed switch, i.e. it's "on" when the temp is below 207degF and "off" above that. You'd need to use a DPDT 5-pin relay to reverse the switch's operation. The relay looks the same, it just a fifth pin in the middle labeled 87a. The circuit is the same, you just connect the fan to pin 87a instead of pin 87.

I still think you shouldn't use that switch. Too hot...

 

I'm not planning on using the switch in the vehicle currently as the whole purpose for the set up is to keep the car from getting overly hot in an already hot running engine, and like you said it's temperature is high. I'm going to take it out tonight and take the sensor to o-rielly's tomorrow and see what they can offer me.

I'd like to come out with a switch that's open-switch with an activation temperature of what, 180 degrees?

Actually maybe you could give me some more advice then? What temperature should the switch be set to come on at? I'd assume it'd need to be slightly cooler than what the engine should be temperature wise. 180 sounds right but I'm just guessing.

 

The relay does two things, one of which is to isolate the sensor from the fan load so that a low amperage sensor can run a high amperage fan.

Secondly, it does exactly what you want.

The SENSOR is CLOSED (i.e. on) at less than 180 deg. and OPEN at greater than 180 deg.

The RELAY is normally CLOSED, operating the FAN.

The sensor operates the relay so:

Sensor CLOSED (cold) causes Relay OPEN causes FAN OFF.
Sensor OPEN (hot) causes Relay CLOSED causes FAN ON.

If you put your sensor in series with the fan, I'm sure the fan's amperage would trash your sensor.

I'm certain AaronCake would have put this in his writeup, since he is usually so thorough.

-Goofy

 

The sensor so far is hooked up to the coil ground side. Other end of coil is connected to fuse then battery.

Fan positive is hooked to 87 I believe, switching means. And negative is directly connected to battery.

Will try and be more specific when I get home and can check it out

 

You shouldn't need to use the fan at any time other than when stationary or moving slowly. If you can't keep the engine temps at under 190degF when just driving around then you have a cooling system problem. If you engine is highly modified and the temp climbs too high under load then the cooling system needs to be upgraded, i.e. a bigger radiator.

You want an adjustable temp switch, not a fixed one.

No, the fan is only supposed to run when there's not enough air flowing through the radiator to keep the engine temp stable. In normal driving the engine will sit at 180-190degF, so the fan shouldn't come on until 190-195degF.