Wiring a LED to my e-fan
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Wiring a LED to my e-fan
I bought an e-fan from Jusnes Modified and installed it a few months ago. My truck is a bit loud and I can never hear the efan in the cab, so I have been wanting to install a LED so I know when the cooling fan comes on and goes off. Yesterday I finally did it, I installed a LED to the power wire and ground wire of the e-fan. I blew the LED within a few seconds of the fan running.
After reading up on it today, I found that the fan runs at a high amperage. Can anybody tell me what I would have to do to run a LED in the setup, so I can tell when the fan is on or not? I was thinking I could run a resistor to the LED, but I'm not sure of what size I would have to use.
After reading up on it today, I found that the fan runs at a high amperage. Can anybody tell me what I would have to do to run a LED in the setup, so I can tell when the fan is on or not? I was thinking I could run a resistor to the LED, but I'm not sure of what size I would have to use.
#3
You just need the right LED. Get a 12 VOLT LED. Connect the + side the fan's positive power wire. Connect the ground to any ground. That all you need to do.
I did this and took it a few steps further. I have three LED's:
* AC Compressor Demand
* Fan Power
* Fan Manual Disable (switched off)
This way I always know what it is doing and what it should be doing.
I did this and took it a few steps further. I have three LED's:
* AC Compressor Demand
* Fan Power
* Fan Manual Disable (switched off)
This way I always know what it is doing and what it should be doing.
#4
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Originally Posted by FireRanger
You just need the right LED. Get a 12 VOLT LED. Connect the + side the fan's positive power wire. Connect the ground to any ground. That all you need to do.
I did this and took it a few steps further. I have three LED's:
* AC Compressor Demand
* Fan Power
* Fan Manual Disable (switched off)
This way I always know what it is doing and what it should be doing.
I did this and took it a few steps further. I have three LED's:
* AC Compressor Demand
* Fan Power
* Fan Manual Disable (switched off)
This way I always know what it is doing and what it should be doing.
LEDs light/blow because of current, not voltage. I used this same technique with my shift **** mod and it's working fine. Simple eletronics:
Voltage = Current * Resistance
Figure out what typical voltage is running for the wire you will be monitoring. Let's say it's 12 volts as it would be in this case.
Now look at the specs for the LED you bought. There should be a forward voltage drop and a current rating. The voltage drop shows you basically how many volts are "lost" to the diode in the LED (I am not an EE, maybe someone else around here can explain that one better). Just understand that your target voltage is your source voltage MINUS the voltage drop. EG:
12 volts and 2.2 volt drop = 12 - 2.2 = 9.8 volts
From here, look at the current rating of the LED. Should be something like 20 milliamps (ma). Now apply it to the formula:
V = IR
12 - 2.2 = 0.02 * R
(Note that current (I) is expressed in whole amps, hence the decimal). Now you can figure out how many ohms of resistance you need to safely drive that LED:
9.8 / 0.02 = 490 ohms
So find a 490 ohm or higher resistor and you should be set. Note that I used a 1K ohm resistor in my shift **** because I wanted to dim the LED more (it was a superbright green LED). I usually round up a bit as a safety factor (what happens when the circuit is 14V? A car power supply is NOT the most steady thing in the world)
Depends on how hands-on you are with electronics. May be easier for you to find and buy a 12V LED... I just mention this as an option.
#5
#6
Originally Posted by FireRanger
You just need the right LED. Get a 12 VOLT LED. Connect the + side the fan's positive power wire. Connect the ground to any ground. That all you need to do.
I did this and took it a few steps further. I have three LED's:
* AC Compressor Demand
* Fan Power
* Fan Manual Disable (switched off)
This way I always know what it is doing and what it should be doing.
I did this and took it a few steps further. I have three LED's:
* AC Compressor Demand
* Fan Power
* Fan Manual Disable (switched off)
This way I always know what it is doing and what it should be doing.
Thats correct.
I have an LED (green) and it is on when the fan turns on. I also have an "off/auto" switch. It allows me to let the fan run in auto (controller) mode, or turn it completely off (for water holes, etc).
I have the LED wired to the positive on my fan, the ground was behind my radio bezel. I wired the switch to interrupt the fan positive, it works great!
I bought my LED and switch at radio shack for under $5
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#8
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Originally Posted by FireRanger
Yes, you could do that. Or you could save yourself the hassle and just buy a package of 12v LED's. There is no functional cost difference in the first place... plus you don't have then buy resistors and solder.
Whichever you end up using, post a pic of the final setup. Would be interested in how you style the indicator lights (I assume on the dash).
#9
Originally Posted by winks
Thanks for the info guys, I remember, VI=R from school (many moons ago). I will look into the 12v LED though, so that I don't have to do all the soldering, etc.
Unfortunately the LEDs that I have are all old ones that I've had for a while, and I don't have any of the packaging.
Unfortunately the LEDs that I have are all old ones that I've had for a while, and I don't have any of the packaging.
i have one on my fan.....the fan from Jusnes you need to tie it into the blue wire that goes from the fan to the controller........
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