led w/ diode for electric fan
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121295
Printed Date: July 09, 2025 at 8:25 PM
Topic: led w/ diode for electric fan
Posted By: kaztheminotaur
Subject: led w/ diode for electric fan
Date Posted: April 11, 2010 at 10:42 PM
I recently put an electric cooling fan in my truck. I have a LED wired in as an "on" indicator light. I discovered that the air speed will turn the fan, when it isn't under power, enough to make the LED light dimly. I know I can put a diode on the fan to prevent back feed but it would be easier to access the LED. Can I put a diode on the LED to accomplish the same thing?
Replies:
Posted By: kaztheminotaur
Date Posted: April 11, 2010 at 10:44 PM
99 Chevrolet Silverado I would put the diode stripe to the positive side of the LED right?
Posted By: oldspark
Date Posted: April 12, 2010 at 2:18 AM
No - it won't stop current to the LED....
I thought you would place the diode across the fan terminals to dynamically brake it (else a resistor).
But that is why people run the LED either from the relay's solenoid/trigger source, else they use changeover relay(s) for the fan(s) - ie, #30 to the fan; #87 from fuse battery; #87a to GND.
Posted By: kaztheminotaur
Date Posted: April 12, 2010 at 4:37 AM
Thanks.
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