This is topic Need help with wiring electric fans. in forum Tech Talk at Northern California Ford Owners  .


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Posted by omarquez510 (Member # 11233) on :
 
Alright guys, I need clarification on wiring my dual fans. This is not a fox application so i'll provide diagrams. This is going in a 5.0 swapped bmw e30. The O.E. bmw dual speed fan is too thick, so I pulled two small fans from a MBenz 190E.

I need to know if the resister before the fan motor is required. Or if I can just give them power and ground via relay.(Last diagram)

MBenz 190E dual fans


BMW Dual Speed fan


If I use the O.E. bmw wiring i would just use the normal speed temp switch and the high speed relay, right?

Ultimately I would love to use the following diagram for my fans. Just wondering what the deal is with the resistor before the fan motor. Can i just copy the diagram below and splice in the second fan?



[ April 23, 2012, 01:35 PM: Message edited by: omarquez510 ]
 

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Posted by Blind (Member # 3052) on :
 
the last diagram there is no resistor before the fan, that's the electrical symbol for ground.

You can only run one fan off each relay, if you want an easy way to wire 2 electric fans I'd recommend this diagram -



Substitute a fan for each of the speed settings on this diagram.

[ April 23, 2012, 01:40 PM: Message edited by: Blind ]
 

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Posted by omarquez510 (Member # 11233) on :
 
Yea, I'm just wondering if I have to carry over the original resistor like pictured in the MBenz diagram.

Or Just splice the fan motors together and use the last diagram exactly as pictured w/o resistor

Got a bigger diagram lol?

[ April 23, 2012, 01:43 PM: Message edited by: omarquez510 ]
 

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Posted by Blind (Member # 3052) on :
 
after looking at them, I think all the resistor does on the MBz fans is reduce the speed of the fan so it runs quieter.

if you want to see my diagram larger, open it in a new tab and hold down ctrl and scroll up with the mouse, it will zoom in like pinching on an iphone.
 

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Posted by Blind (Member # 3052) on :
 

quote:

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Originally posted by omarquez510:
Yea, I'm just wondering if I have to carry over the original resistor like pictured in the MBenz diagram.

Or Just splice the fan motors together and use the last diagram exactly as pictured w/o resistor

Got a bigger diagram lol?

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if you just splice the fan motors together off a single relay like your last diagram you may start a fire as the relay overheats worst case, best case the relay will work for a very short time before it gets melted/stuck in one position (Either on or off)
 

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Posted by omarquez510 (Member # 11233) on :
 
I got you. Thanks for the heads up.

Going to draw a diagram and post it up later today.
 

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Posted by omarquez510 (Member # 11233) on :
 
Couldnt figure out libreoffice Draw on Ubuntu. So i drew something up.

Basically going to use the O.E BMW temp switch and relays. Going to ditch the resistor. This was the easiest solution I found. Is it going to work?


 

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Posted by omarquez510 (Member # 11233) on :
 
Basically the only modifications to the stock wiring. Sorry about the huge pics.


 

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Posted by Blind (Member # 3052) on :
 
that looks like it should be fine, might be loud when both fans kick on to full power though.
 

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Posted by omarquez510 (Member # 11233) on :
 

quote:

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Originally posted by Blind:
that looks like it should be fine, might be loud when both fans kick on to full power though.

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Right on, thanks for your help.
 

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Posted by 5.0 Pro (Member # 6311) on :
 
A grounded switch would be alot more safe and most temp sensors go to ground, even if it doesnt you only have to run one wire to the sensor instead of two. plus all the wiring you run to a switch is a ground so no chances of shorting later on down the road. Also no need for a 3 position switch or diode thing. I modified your picture to show a grounded toggle switch configuration where when key is on fans would be temp controlled and when switch is on the temp sender would be overriden. Also the light will be on anytime fan is active. Just something to think about. your diagram above would also work fine as well.



[ April 23, 2012, 06:14 PM: Message edited by: 5.0 Pro ]
 

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Posted by Wrenchin (Member # 9529) on :
 
Honestly, go to vic hubbard and buy the adjustable fan controller. The wiring is a hundred times better. Just need power, ground. Put the aluminum sender near the upper hose, adjust your temperature based on your preferences.
 

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Posted by Blind (Member # 3052) on :
 

quote:

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Originally posted by Wrenchin:
Honestly, go to vic hubbard and buy the adjustable fan controller. The wiring is a hundred times better. Just need power, ground. Put the aluminum sender near the upper hose, adjust your temperature based on your preferences.

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