Looking for 2 speed electric fan schematic

[mc1984ss]

I recently purchased a new 2 speed cooling components electric fan. They give you the option to wire it as a single speed but I would like to wire it as a 2 speed. Can anyone provide me with a proper schematic for this with relays? I have a diagram on how to wire it as a single speed but not a double. I contacted the manufacturer and instead of providing a schematic they suggested I buy thier controller. I do not want the controller I would like to build my own harness with relays and temp sensors. Thanks in advance!

[andrewb70]

Is your car EFI? What engine management are you using?

Andrew

[mc1984ss]

It is currently carbureted

[andrewb70]

It is currently carbureted

To be honest, the best thing you can do is use the DC Controls pwm fan controller. If I had a carbureted engine, that is what I would use. I am sure other people will chime in with other suggestions.

Andrew

[CapSS92]

There are tons of ways to wire a two speed. Too many to list actually. Here's a google search link. Pick your poison.

https://www.google.com/search?q=2+sp...Olyacgt6lYU_0M

[GoodysGotaCuda]

The most effective but most expensive way will to use a pwm soft start controller and wire it to the high speed circuit of the fan. Done. Easy and will work very well!

https://derale.com/product-footer/el...n-probe-detail

The more old-school way will be to use a 5-pin and a 4-pin relay to control both speeds. There are quite a few diagrams out there on the internet to do this, and you will need either two adjustable thermostatic switches, one at one temp and one at another temp. Or two different sending units, which will be more troublesome.

It's cheaper, but I'd really suggest just dropping the $100 or so on a PWM controller and be done with it. It will not sound like a hurricane when it doesn't need to, it's easier on your charging system and will work without much thought or excessive wiring.


The diagram below is a generic two relay configuration to control high and low. One is a 5pin and one is a 4pin.

• The low relay is grounded when the 85pin on the right relay is grounded by the thermostatic switch.
• The low relay is control power is provided by the 87a pin on the high speed relay
• If the temp is high enough and the high temp switch grounds, 87a switches to 30 on the high speed relay, which removes the ground from the low speed relay. The low speed relay stops providing power.

[mc1984ss]

I see that Dakota Digital also makes a fan controller. Is this the same as the derale and the DC controls? Are all three of them soft start? Thanks for the help, everyone I'm learning

[dhutton]

I see that Dakota Digital also makes a fan controller. Is this the same as the derale and the DC controls? Are all three of them soft start? Thanks for the help, everyone I'm learning

Nope. It is a crude relay based controller. The two speeds are one fan and two fans on high...

Don

[GoodysGotaCuda]

I see that Dakota Digital also makes a fan controller. Is this the same as the derale and the DC controls? Are all three of them soft start? Thanks for the help, everyone I'm learning

I am not familiar with it, but it needs to say pwm/Pulse Width Modulated, duty cycle, varying speed, soft start, etc. somewhere in the description.

[andrewb70]

DC controls is best.

[dhutton]

Here’s a new option from Carl’s new company:

https://www.powersystemsmanagement.com/products/

I’m going to use one in my current build

Don

[dhutton]

I am not familiar with it, but it needs to say pwm/Pulse Width Modulated, duty cycle, varying speed, soft start, etc. somewhere in the description.

It uses relays so can’t do any of those things...

Don

[CarlC]

To be honest, the best thing you can do is use the DC Controls pwm fan controller. If I had a carbureted engine, that is what I would use. I am sure other people will chime in with other suggestions.

Andrew

Why yes, yes I will...... ;-)

https://www.pro-touring.com/threads/...27#post1330527

[mc1984ss]

Goody, I like the schematic you posted using the 5 wire relay. Is there a way to wire it so it only turns on with the ignition switch on? I like the controllers but I also like the simplicity of being able to just swap a relay or bypass of necessary