Extra wire on positive battery terminal

Guys I need some help identifying this wire thats on the positive side of battery post. Its a smaller gauge and looks like its for a aftermarket device definitely not oem. I'm not sure if it's for an alarm addon or an amp wire? The battery lost its charge on the truck because I haven't driven it for more than a month. When I got back home I was able to jump the battery and it ran fine. I'm thinking it can contribute to some sort of parasitic drain for the battery? The wire leads right off the battery to a small dnf amp box its says 300A on it. The wire seems to be going towards the driver side looking at it from the hood. I've attached some pictures to this thread. My truck is a Tacoma 08 V6 4WD TRD 4.0L Double cab. Any advice would help! Thanks

 

Keep following the wire. Probably goes through the firewall with the main harness then to whatever it’s running

 

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Now try and track that wire down from the inside and see where it goes.

 

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Starter wire?

 

that box is a fuse holder commonly used in stereo installs. if you track it down and don't find a connection then just remove it. if it doesn't connect to anything past the fuse box there was no parasitic drain and it's just your old battery.

 

Dumbass PO has a wire that’s fused well beyond its current rating lmao, if that’s a 300A fuse.

Unbolt it from the terminal before you do anything else. That’s a potential fire hazard.

then trace and remove.

 

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