Electrical short

The short answer is yes, but let's take a step back and use a different way to confirm this fuse is the cause of the issue because even though I understand the sparking may point us in the right direction it is not definitive.

We need to test for the battery draw. This guide talks about this issue but I will give more details to properly address this:

https://www.2carpros.com/articles/car-battery-dead-overnight

Please see the diagram below and that will explain how to set your meter up in series with the battery so that we can confirm this fuse is the cause of our issues.

Then we need to get a picture of the fuse you are removing so that we can be sure we are on the right circuit. Then we can figure out what is causing this on that circuit with the proper diagram of the system.

Please see below and let me know what amperage you have with the fuse in and out.

Thanks

I see you noted that you had done all this, but did you record what your amp draw was?

Not knowing what the draw is will not confirm this is the issue. At this point, the ECM could be the issue, but we need to test the draw and then unplug the ECM and see if the draw goes away. However, if you get the draw to go away then it could also be something that the ECM powers that is keeping it awake.

Hence the need to go through this using the testing I talked about. Otherwise, we can just replace the ECM and see what happens. That does make the most sense, but I would not want to make that decision based on just this because while it may fix it, the proof is not there yet to be confident that this will fix it.

Okay. Got it. That makes sense. Then I agree that the ECM is the likely issue.

Basically, all electrical accessories are turned off while cranking because we need all available amperage to go the starter.

So, if you turn to start and everything cuts off, but nothing happens then it could be an ECM.

However, we need to confirm this by checking voltage at the park neutral relay. If you look at the wiring diagram you start circuit goes through two sides of the relay. Basically, it sends voltage through the park neutral switch and if it is in park or neutral then there is a path to ground, and it closes the relay to send power to the starter. Technically the ECM does not control this.

Before you get too far down this path though, since you had an issue with the battery draining overnight, we need to take the battery into a parts store and have it tested.

https://www.2carpros.com/articles/car-battery-load-test

A drained battery that may show 12 volts on a meter may not be able to start a car so this is where we should start but especially since there was an issue with it. Even if you charged it, it may not be able to hold the charge and it will cause this.