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led rocker to toggle a fuse?

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=134652
Printed Date: April 27, 2024 at 8:04 AM


Topic: led rocker to toggle a fuse?

Posted By: tortuousaugur
Subject: led rocker to toggle a fuse?
Date Posted: August 02, 2013 at 7:55 PM

I'm curious if it is possible to toggle a vehicle fuse with an on/off LED rocker switch? I've been looking at other diagrams, but for the most part, it seems that the LED requires to be connected to a power source.

The outcome of this project is to be able to toggle a switch on or off depending on whether I want the fuse in or out, and would like to have the LED powered while the fuse would be closed.

Any help would be greatly appreciated.



Replies:

Posted By: oldspark
Date Posted: August 02, 2013 at 9:22 PM
It makes no difference what you are switching - the LED indicator still requires a GND.

I presume you will wire the switch across the fuse so that when on, the fuse is shorted out.
The problem is that if it's a common SPST switch, both terminals of the switch will be live at all times and hence the LED permanently lit - unless the fuse blows and the switch is off.
To be lit only when the switch is on (or off) requires a DPST (or DPDT) switch.




Posted By: tortuousaugur
Date Posted: August 03, 2013 at 8:57 AM
Sorry, guess I left some details out.
Currently, my switch has three connector prongs labeled one to three, the third prong being a copper colored prong, which I'm reading is the ground. Prong one should be the positive power, and two the negative/accessory.

The fuse I will be hooking this up to will have already been modified to no longer work on it's own (I will either use a burnt fuse, or use a drill to break the connection between the prongs). Completing the circuit will only happen when I toggle the switch on.

Just looked at the switch's packaging, and it is indeed a SPST switch. Is there any way to wire this safely, or is grounding a fuse port outlet a bad idea? It's important that the port that this is all dealing with does not function when the switch is off. Would I just have to get the correct polarity going to the correct switch pin, and then have a connection from the switch's GRND to the vehicle's chassis, or would there be an easier way to ground the LED? Is it possible to have the fuse connected in such a way that prong two and three both connect to the same side of the fuse, and prong one the other side? Using a 9v battery to test how the LED lights up or not, this may be the way to do what I want to do.




Posted By: tortuousaugur
Date Posted: August 03, 2013 at 9:06 AM
Never mind, I'm complete newbie at this. Shorting like that makes the LED not light up. Maybe it would be best to wire a 9v battery to the LED, and have the fuse on the normal switch function.

Barring any other idiot mistakes I would have made with this scenario, this would work perfectly, right?




Posted By: oldspark
Date Posted: August 03, 2013 at 12:26 PM
That would work - a 9V battery or other independent supply with its -ve to the LED GND/-ve & +9V to the input of the switch (the terminal opposite the LED GND).
The when the input connects to the center terminal (LED+) it complete the batt+ - LED - batt- loop.

Good idea.
Damn newbies that reckon they know nothing - yet it seems they are very capable of thinking.   posted_image posted_image





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