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proofread electric fan diagram please

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Hi. I made this diagram for a 2 speed electric fan (pirate 4x4 mentioned that taurus fans are cool *yuk yuk* http://www.pirate4x4.com/tech/taurus/index.html ) that i plan to grab this weekend. I studied this diagram on turbobricks.com http://www.turbobricks.com/mods.php?content=toyofan


and made this diagram in photoshop.

RH - relay for high circuit

RL - relay for low circuit

TS - thermoswitch


It's supposed to allow the whole deal to be turned off for the freeway or water crossing (which i do all the time :moon: ).

Also, the light is supposed to turn on when the thermoswitch closes unless the high circuit is in operation.


I don't know enough about electrics to know if I got this right! please criticize!


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Looks like it'll work to me.


You could even add a second LED for your thermoswitch. That way you'll know if it's running at all times. I'm assuming you want the thermoswitch to actuate in the "low" setting, when it reaches 85F or whatever.


Good luck, John

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2 thermoswitches would be ideal but the radiator isn't set up to accept another one, i think.


thanks John.


My soldering iron is 40 watt. should i get a stronger one so it chases less heat up the wire as it gets hot enough to melt the solder?


also, re: the taurus fan

"they reportedly draw 33 amps continuous, and up to 100 amps at startup!" - from the pirate post. Is this going to overload a stock subaru alternator/battery?



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Let me see if I understand what you are trying to do here:


"Low" mode - actually 2 possibilities here. The fan will be "off" until the thermoswith actuates. Then it kicks the fan onto "low speed"


"High" mode - again two possibilities "off" or "high" fan speed.


The LED will only tell you if the fan is "on" in either hi or low, so you only really need one under that scenerio.


Hmmm....Maybe the setup you really want is something that cycles from "off" to "lo" to "high" automatically depending upon temp. Do you know if the Tauras had a dual temp thermoswitch or 2nd sensor? Maybe if you are lucky, the Taurus has a dual temp sensor that will thread right into your rad.


Even if not, there are other places along the cooling system where you can install a second sensor to get a temp reading. If your Sube came with dual electric fans, you might be able to adapt that setup since there are two temp ranges. Then, its just a matter of sending the signal with the higher temperature threshhold to the "high" terminal on the fan.


A little more complex, but it can be done.


good luck, John

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hi John. thanks for the reply. I intended for the thermoswitch to be part of the high circuit. The LED should come on when the thermoswitch activates unless the high circuit is already on, instead of the low circuit.

Here's another diagram. I started with one known to work from the volvo site. The red dots are LEDs, or where they could go anyway. I'm going to run this by an auto electric shop today while i errand.


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Looking over your diagram it looks like you can use what you have except for the LED's. You need to tie the anode side of the led to positive side of the fan motor connection and the cathode side to ground. The thermo switch LED will need to have a lead run from a positive 12v source connected to the anode of the LED. The cathode lead then needs to be tied to other side of the thermo switch. This will make the ground for the LED when the thermo switch closes. You will also need to add a current limiting resistor in series to the anode of each LED unless you purchase the type that already have one. Using a 2 thousand ohm, half of a watt resistor should work fine for the series resistors.


If you want to eliminate the kill switch you can use an on-off-on single pole double throw type switch. The center position will be the kill position.

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Hi Glen.. thanks!

I was lazy in illustating the LEDs but i needed proper install info for them too. I see what you mean about the switch too. thanks a lot!

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