Electrical How to wire a small light to show fan status?

G

ggradtech

Active Member

Jun 17, 2016

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May 1, 2020

#1

• May 1, 2020

• #1

I have a Contour dual fan setup, and it works great. It moves tons of air, and I can almost always “hear“ it when it’s on. Sometimes with the AC on it’s hard to hear it though. Is there a simple way to wire up a small dash light to show when the fans are “on”? If someone could draw me a simple diagram, that would be great. Im thinking maybe a 1-2 A in-line fuse would be good also for safety reasons. I “think” a wire on the fan relay would be used for the light. Not sure how to wire/ground it exactly though. Thanks

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

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Massachusetts

May 1, 2020

#2

• May 1, 2020

• #2

Easiest way would be to wire it intot he relay or controller turning the fan on or off. Tap a wire into the power output, run it to your signal light, and then ground it on the chassis.

It would just tell you that the fan is commanded to be on. If you actually want a light to tell you if the fan is actually spinning...a little more complex.

 

Blown88GT

Founding Member

Nov 13, 1999

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Palm Beach Gardens, FL

May 1, 2020

#3

• May 1, 2020

• #3

A 12V LED across the fan.
The reversed biased diode is a "freewheeling diode" to clip the voltage spikes when the fan turns off.

I replaced the relays with a DCC PWM soft start controller. Still have the indicator light & FW diode.
This setup was for a Mark VIII fan which flows 4500 cfm vs the Contour fans at 3500 cfm.
The Mark VIII wouldn't fit any more, now have the Countour Fans.
The Contour fans use about half the amps of the Mark VIII, which needed the 75A motor relays shown in the diagram.
Mark VIII with relays draws 105A on startup & 42A running. Never measured the Contour fans.

 

Last edited: May 1, 2020

KRUISR

10 Year Member

Apr 16, 2015

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May 4, 2020

#4

• May 4, 2020

• #4

I used 2 lighted toggles (one for high speed, one for low speed).



One switch is blue, one red. Picked up a local auto parts store, nothing special.

For wiring, I took 12V power from cigarette lighter in console into switch. Power output from switch I spliced in with the switching signal into my relay (power from my temp controlling switch to trigger the relay). The third blade is for ground to make light come on. The outcome, I have a override toggle that will also light whenever the temp controller turns the fans on. No fuses or diodes were added or used.

Ashtray was removed for install of flat panel. Switches are low enough profile that I can still close the cover. Functional and stealthy.

 

Reactions: JD1964

JD1964

there is enough sticking out to grab on to

15 Year Member

Jun 28, 2013

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May 4, 2020

#5

• May 4, 2020

• #5

Cut one of the fan blades off. It will be so out of balance you'll know for sure when the fan is spinning.

 

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LX1993

5 Year Member

Jan 4, 2018

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May 8, 2020

#6

• May 8, 2020

• #6

You could also put a current sensing relay on incoming power to the fan. Come off that same leg of power to the csr, other side to light, then ground the light. Pretty straight forward run proof.

 

KRUISR

10 Year Member

Apr 16, 2015

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May 8, 2020

#7

• May 8, 2020

• #7

74stang2togo... what do you disagree with? This is how my toggles/lights are hooked up and work great. What is not right?