To make a long story short, someone installed a wire from the battery to some speakers in the trunk. That wire broke and I didn't know it. The day it broke, the car had been running really rough and had no power when i tried to drive it. It stalled a few times and the transmission arrow came on right before. Sometimes when I would rev it in neutral and put it in drive, I could drive it again. Later on, I found the live wire sitting on the transmission. I took it off and disconnected it, hoping the problem would go away. But it must have blown a sensor or something. What parts could that have affected?

 

my uneducated guess would be that it may have put strain on your alternator, causing it to go out.

I'm sure others here have a better idea of what could have happened though.

 

I do not know what that wire from the battery was going to, but I don't think it went to a speaker in the trunk. That just does not work.

 

It would be going to an amplifier in the trunk, which powers the subs, or speakers. There is typically an in-line fuse right after the battery, but it must not have blown.

 

I have seen this happen a few times. Look at your positive battery cable. On the terminal, there's a stud where a group of wires attaches with a ring terminal. This is actually the main connection to the car's entire electrical system. The thick battery cable is merely the load cable to the starter! That means that that connection carries a LOT of power. Sometimes, that connection can corrode, which creates resistance, which causes heat, which causes further corrosion, which creates more resistance... you can see where I'm going with this. I'll bet that amp cable was connected to that stud, too- it's a convenient place to do it- but it's also a bad place to do it because of how much current that connection handles in the first place. Check the nut- is it loose? Feel the cables- are they hotter than the rest of the terminal after the car's been running? does the insulation on the wires look discolored/ feel hard? Take the nut off and clean the ring terminal, stud, seat on the battery terminal, and nut with a wire brush. Coat everything with petroleum jelly and reassemble. If the wires themselves are badly discolored and corroded, you'll need to replace the ring terminal- not a job I'd recommend DIYing unless you have the proper type of heavy- duty crimper and can use a good soldering iron- that connection carries about all the current it can handle even when it's done right. Connect it poorly, and it'll go right back to hell in a hurry. However, cleaning it usually does the trick.

If this doesn't cure the problem, you blew something else. Check the alternator first, then start playing with a code reader/ scanner. Good luck!