Electronic – Why does grounding the switch cause the fuse to blow

short-circuitswitches

I'm working on restoring an old ATV, and I'm having a bit of trouble with the wiring. When I got the ATV it was missing the ignition switch, so I decided to replace it with this awesome looking switch instead.

12V switch

Which I'm guessing, internally looks something like this…

Switch internal

After looking at the wiring diagram, I've figured out how to connect the switch.

ATV wiring diagram
Click for larger view

When I install the switch like this, the ATV powers up.

Switch Connected No Ground

However, when I ground the switch so the LED will light…

Switch Connected With Ground

The fuses blow.

If I don't connect the ground and I connect the pink and black wires to the switches Ground terminal, the LED lights but the ATV is not powered up.

How can I connect the switch so that it turns the ATV on, and the LED on the switch itself also lights?

Best Answer

You need a resistor between the LED pin and ground. Try anywhere from 220 to 1K ohm. The LED, being a type of diode, will allow as much current as it can if directly connected from power to ground.

If it blew a fuse, it's possibly blown the LED too... but you may be lucky.

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