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KiLLeR2001
03-08-2008, 10:24 AM
I've got a simple question to ask... I have a kill switch that interrupts in between the ECU and the redish/brown plug harness by the passenger side headlight (s13). The switch is rated at 15A. But the signal itself is a negative signal. I was wondering if I need to fuse this at all with a 10A (considering the size gauge of the wire) in order to protect my ECU from any damage. I know if it was a positive wire I would do it, but does the same idea apply for a negative signal?

Thanks.

Big Bronze Rim
03-08-2008, 11:23 AM
In theory the same concept applies, however, you want your fuse upstream (positive side) of whatever it is you are trying to protect. It sounds like you are just switching the ground with your kill. The ECU should already be fused so you really don't need an additional fuse on your ground.

g6civcx
03-08-2008, 11:30 AM
the signal itself is a negative signal

What does this mean? Electrons travel from ground to the (+) terminal on the battery.

What does a negative or positive signal mean? Anything in a circuit will see electrons flow pass. The direction of the flow depends on ground and source.

Why does a fuse care which way the electrons are flowing?


There are some serious deficiencies in your question. I suggest you brush up on high school physics, research how a fuse works, and then check back with us.

KiLLeR2001
03-08-2008, 02:12 PM
In theory the same concept applies, however, you want your fuse upstream (positive side) of whatever it is you are trying to protect. It sounds like you are just switching the ground with your kill. The ECU should already be fused so you really don't need an additional fuse on your ground.

Just the answer I was looking for.

What does this mean? Electrons travel from ground to the (+) terminal on the battery.

What does a negative or positive signal mean? Anything in a circuit will see electrons flow pass. The direction of the flow depends on ground and source.

Why does a fuse care which way the electrons are flowing?


There are some serious deficiencies in your question. I suggest you brush up on high school physics, research how a fuse works, and then check back with us.

I think you're thinking way ahead of yourself. The basis of my question was simple. Not sure how you misinterpreted it. Thanks anyway.

g6civcx
03-10-2008, 10:37 AM
I think you're thinking way ahead of yourself. The basis of my question was simple. Not sure how you misinterpreted it. Thanks anyway.

Your question is very convoluted and not clear. Anyone with a basic understanding of electronics will not be able to understand.

I have no idea what your circuit looks like so I can't comment.

Even if the component is downstream from the ECU, you may still need a fuse depending on the gauge, where the power is coming from, how the power is diverted.

There are a lot of design considerations that you are not aware of, and it's not clear from your question what exactly you're trying to do.