Most likely it is an accesory wire.Some cars come with options that would use that wire some cars may have auto dimming head lights and some don't but the factory uses the same harness. Factory harnesses always have extra leads.
The wire from the battery to the starter does not include a fuse.
you have a short somewhere likely bare wire coming in contact with steel and this drains battery.
There is a wire next to the large (red) battery wire that is for the tachometer. Check to see if you plugged it back in and is the connection good.
To fix a burned wire that is plugged in at the fuse box under the Battery sign, the wire will have to be removed and a new one soldered in place. Before doing this, find the cause or overload that caused this wire to burn in the first place. It could be that a fuse of too high an Amp was placed in the fuse box by mistake.
1. open trunk2. remove floor boards ( 2 layers)3. you will see the battery on right side near the spare wheel4. loosen ground wire clamp (black wire) and remove it first from battery post5. disconnect red wire6. replace battery, secure it and connect RED wire first7. connect black wire
Follow the positive cable wire from the battery and it will end up plugged right into the safety switch.
The front o2 sensor is just to the left of the battery. It's a little tube with a wire that is plugged in right before the exhaust pipe.
It could be when the positive wire is plugged in the negative slot and the negative wire is plugged in the positive slot. This can make the readings negative.
You need to learn what one looks like and find where yours is. You need a couple of tools to remove and reinstall the battery wire connection and the hold down fixture or bolts. LOL
Likely a inline type (fuseable link wire) look for a section of wire usually near the battery that is discolored or try to stretch the wire they can burn off or break internaly, test this wire at back of alternator with test light and engine and key off, you should have power at the output terminal as long as the battery cables are connected.
You can use a battery in any electrical device that does not require being plugged in. All mobile vehicle with and electric starter uses a battery(usually placed under the hood or bonnet or close to the engine) you can however relocate the battery into you trunk/boot or where ever you want it to be along as you have the proper wire size.
It's right next to the transmission oil filter. It has a two-wire connector plugged into it. NOTE: if you have a manual transmission, there is no trans fluid temperature sensor.