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2/15/2019 8:03 AM  #1


Electric Fans

I'm installing dual electric fans from a late model ford that are supposed to pull like 3500 cfm.

I'm thinking I want  to wire these up so that they come on separately to avoid a larger amp draw all at once or have both come on but on slow speed then go to high when they reach a set temp.

Any feedback from anybody on how they have wired dual electric fans ?  I may just use relays and a typical sensor to trigger or may use one of the controller boxes that offer the variable speed option.

I'm thinking also mounting the relays and or controller box right on the fan shroud?  good idea or no?

Definitely plan to have an override switch as well as switch on from my vintage air.

thanks and sorry for all the questions this week. Trying to get some stuff done.

 

2/15/2019 9:31 AM  #2


Re: Electric Fans

Speed control is IMO unnecessary and an added level of complexity.  With a thermostatic switch you can set an on temperature and an off temperature.  With two fans you have several options for wiring.  A lot of the OEM dual fan setups only run one fan for cooling unless the ECT starts to rise past a certain point.  The second fan is basically just setup to run when the AC is engaged, or in an emergency.

Personally I would just go with a relay system.  Easily constructed for about $30 in parts.  I don't see an issue with mounting the relays to the shroud.  Mine are mounted on the fender apron within 6" of the shroud.  If I didn't already have my headlight relays there I might have gone shroud mounted. 

 

2/15/2019 9:42 AM  #3


Re: Electric Fans

Good info

I have 130 amp 3g alternator so I have plenty of charging capacity.

I wonder if I can wire it up so one fan kicks on at say 185 and the second kits on at a little higher.  Guess I would need two sensors to make that happen. Maybe I'm just overthinking it.  LOL

Guess I need to figure out where to install the thermostatic switch since my intake port has temp sensor for water temp gauge and don't think my thermostat housing has a port.

     Thread Starter
 

2/15/2019 10:02 AM  #4


Re: Electric Fans

No, that's not a bad idea.  Yes, you would need two switches to do that, but the wiring is fairly easy.  You set the relays up with power all the time, and then use the various switches to breaker ground.  I would wire an override switch for each fan, a thermostatic switch for each fan, and then set one so it comes on immediately when the AC compressor kicks on.  Give me a couple hours I'll come up with a wiring diagram for you.  Might need three relays to make it work, might be able to do it with just two.  Let me play with it a bit.

 

2/15/2019 10:16 AM  #5


Re: Electric Fans

I faced this challenge when wiring up a pair of big SPAL fans for my Lightning. They have a massive inrush current so you have to plan your relays and wiring accordingly. It's definitely a good idea to stagger the fans coming on. You might also want to consider turning at least one fan on automatically when you kick the AC on if you have AC. I would recommend a good controller, there's quite a few out there that make it pretty easy and are very adjustable.

If you're interested I could share my BDWD (big dumb wiring diagram), but it got out of hand pretty quick with AC control, WOT cutout, AC high side pressure cut, etc, etc.

 

2/15/2019 10:26 AM  #6


Re: Electric Fans

Here, this should work.  It will take three relays, but allows each fan to be set for a different temperature, provides override for each fan, and automatic triggering of one fan when the AC compressor comes on.

Last edited by TKOPerformance (2/17/2019 6:07 AM)

 

2/15/2019 12:39 PM  #7


Re: Electric Fans

mounting the fan relays on the shroud IMO is just messy and a bad idea

I have mine mounted close to where the regulator is and wrapped everything in blac electrical tape to match the factory wiring, and soldered wires instead of using any other connectors (except for the fan disconnect)

you can make that circuit that TKO suggested, or go with the premade ones depending on how much money you want to spend. SPAL has one thats variable speed .. I am using Derale 16759 which works very well. Variable temp, not speed.


If it aint broke, I have'nt tried to "Fix" it yet!
 

2/15/2019 2:40 PM  #8


Re: Electric Fans

Thanks for the diagram TKO.  Shouldn't cost much to put this together.

I see you penciled in the Hayden controllers.  You used these before ? 

Wasn't sure how the probes work in comparison to the sensors that sensors that mount like a sending unit.

 

     Thread Starter
 

2/15/2019 3:19 PM  #9


Re: Electric Fans

Yes, its what I run.  It takes a bit of fiddling to get them set right, but once done they seem to be foolproof.  I haven't touched mine since I put it in a couple years ago.  Brings the fan on at 195 and shuts it off at 180 based on where I have it set. 

 

2/15/2019 7:07 PM  #10


Re: Electric Fans

I was thinking about picking up one of these. A bit more expensive than the relay set up, but soft start, variable fan speed, and run time after engine shut off are nice features.  These seem to get good reviews.

https://www.autocoolguy.com/home

 

2/15/2019 9:40 PM  #11


Re: Electric Fans

1fststang wrote:

I'm installing dual electric fans from a late model ford that are supposed to pull like 3500 cfm.

I'm thinking I want  to wire these up so that they come on separately to avoid a larger amp draw all at once or have both come on but on slow speed then go to high when they reach a set temp.

Any feedback from anybody on how they have wired dual electric fans ?  I may just use relays and a typical sensor to trigger or may use one of the controller boxes that offer the variable speed option.

I'm thinking also mounting the relays and or controller box right on the fan shroud?  good idea or no?

Definitely plan to have an override switch as well as switch on from my vintage air.

thanks and sorry for all the questions this week. Trying to get some stuff done.

 
What late model ford did you get the fans from?


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

2/16/2019 6:34 AM  #12


Re: Electric Fans

Chaplin wrote:

I was thinking about picking up one of these. A bit more expensive than the relay set up, but soft start, variable fan speed, and run time after engine shut off are nice features. These seem to get good reviews.

https://www.autocoolguy.com/home

Interesting features, but pretty spendy.  These could all be added for a few dollars to any relay setup with the addition of some simple circuitry and minor wiring changes. 

I'm really particular wit how I do this type of stuff.  To me, the simpler a device is the better, because there's less to potentially fail.  It seems crazy, but I've seen a lot of times where something as cheap and stupid as a capacitor caused the failure of a $700 computer because the manufacturer spent $0.23 on the cap instead of $0.45 for one that would handle heat better.  These guys definitely seem like they would be the type to use quality components, but the more complicated something is, and the less you understand it, the less likely you are able to effect a roadside fix should the need arise. 

 

2/16/2019 7:41 AM  #13


Re: Electric Fans

BillyC I believe they were from a Ford Contour. 

I had researched online and a lot of people were using this fan set up with good success.  I bought it new from online supplier for not a lot.  I can look up the paperwork if you want more info on it?

The fans are supposed to pull about 3,500 cfm.
 

     Thread Starter
 

2/16/2019 9:51 AM  #14


Re: Electric Fans

1fststang wrote:

BillyC I believe they were from a Ford Contour. 

I had researched online and a lot of people were using this fan set up with good success.  I bought it new from online supplier for not a lot.  I can look up the paperwork if you want more info on it?

The fans are supposed to pull about 3,500 cfm.
 

 
If possible I'ld like to know the year Contour so I can watch for one at the local pick n pull. Thanks.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

2/16/2019 10:58 AM  #15


Re: Electric Fans

I've ran a DC controller for over 10 years and works really well.    http://www.dccontrol.com/Multispeed.htm

 

2/16/2019 12:20 PM  #16


Re: Electric Fans

BillyC wrote:

1fststang wrote:

BillyC I believe they were from a Ford Contour. 

I had researched online and a lot of people were using this fan set up with good success.  I bought it new from online supplier for not a lot.  I can look up the paperwork if you want more info on it?

The fans are supposed to pull about 3,500 cfm.
 

 
If possible I'ld like to know the year Contour so I can watch for one at the local pick n pull. Thanks.

1995-2000

This article lists a couple other cars that used the same fan set up.

http://www.mustangandfords.com/how-to/engine/mmfp-0907-thermostatically-controlled-electric-fan-upgrade/


 

 

2/16/2019 12:31 PM  #17


Re: Electric Fans


Good work ain't cheap, Cheap work ain't good!   Simple Man
 

2/16/2019 12:59 PM  #18


Re: Electric Fans

Had a brand new 2011 Ford Flex. The car was disabled when the fan controller went out on the highway. Simplest is best.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

2/16/2019 11:42 PM  #19


Re: Electric Fans

TKOPerformance wrote:

Here, this should work.  It will take three relays, but allows each fan to be set for a different temperature, provides override for each fan, and automatic triggering of one fan when the AC compressor comes on.

 
You might want to move that lower override switch to the relay #2 ground instead of routing the 12V + relay output from that relay to ground via that switch.

Otherwise pop goes the weasel!

Edited to remove old schematic... less confusion!

Last edited by 351MooseStang (2/17/2019 6:15 AM)

 

2/17/2019 5:44 AM  #20


Re: Electric Fans

Yes, good catch.  The second override switch should go to the wire below it, not above. 

I changed it and removed the old pic so there was no chance of confusion.  Thanks again.

Last edited by TKOPerformance (2/17/2019 6:08 AM)

 

2/19/2019 3:21 AM  #21


Re: Electric Fans

I have a spal fan control tucked away some place .If you are interested in it let me know .Removed it when I went to fuel injection.


If its worth doing do it right !
 

2/19/2019 11:06 AM  #22


Re: Electric Fans

Yeah I might be interested in the Spal control

     Thread Starter
 

2/19/2019 11:07 AM  #23


Re: Electric Fans

Yeah I might be interested in the Spal control

     Thread Starter
 

2/19/2019 6:32 PM  #24


Re: Electric Fans

Send me a message ,if your interested .Maybe we can work something out.


If its worth doing do it right !
 

2/27/2019 1:14 PM  #25


Re: Electric Fans

Still debating how I want to run the dual fans and need to confirm they can run 2 speeds which I believe I read they will.

After researching some I found that I can buy a temp control switch that has dual temp sensor in one unit. Low speed triggers at 180 and high at 195.

Trying to think thru if I were to use this I could easily figure out how to trigger the first fan at 180 then turn on the second at 195. That would take load off the relays and such by not having both kick on high at the same time.

What I'm trying to figure out is can I wire it up so both kick on low speed at 180 then both kick on high if it reaches 195?

I also found a Volvo 2 speed relay system that sounds like it might work well with this sensor.

Any thoughts on using these components  or experience with them?  If I use a single temp sensor to turn them both on at same time on high what kind of issues might I experience?  I am running 130 amp 3g alternator. Below is the info on the volvo relay set up.

I'm want to keep it simple as possible but very reliable.




 

     Thread Starter
 

Board footera


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