So was Autozone wrong....?

they could be wrong, but they could also be right and they are in the right and aren't trying to get you to just waste money. most common problem seen in car charging system malfunction is the batter is dead, so you replace the battery number one, right or wrong on that its preventive maintenance and a good thing to do anyway. next thing is next, if that cable is bad then there is no way for the alternator to be able to charge the battery. That cable is the only thing going from the alternator to the battery and is pretty much like a "bridge" and current is like traffic. if part of a bridge is down to where it slows traffic, it slows everything down and is less effective for the job its designed to do. if not enough current is getting across the "bridge" then the battery isn't charging well enough meaning it wont have enough juice to start the vehicle. last and most expensive to replace is your alternator, that's why this is done as a last resort unless they know for a fact its dead. There could also be something still on in the vehicle causing the battery to drain while its off, you can never really be too sure when it comes to electrical without checking. My biggest advice tho, which may be a little bit odd, but for the cable to be replaced there is a better way to get it done that is more reliable and can possibly be a lot cheaper than going to a mechanic. Find a local car audio store and tell them you want a "big 3" upgrade done on your alternator. they will replace all the wiring for the alternator to bigger, better wiring. we usually do this for high powered audio systems, but its a good thing to do even on a stock vehicle because it ensures nothing goes wrong in the wiring aspect of the charging system. car audio installers know more about charging system problems than autozone and mechanics. that's one thing you would never think of, but truth is we know them back and fourth and what works well to be efficient and reliable to safely operate extra electronics without damaging anything. An audio installer will be your best friend on this one, trust me. mechanics just know how to replace parts and test parts for deficiency, car audio installers will find the problem and fix it better than how it was. the wire we use also is only around $2-3 a foot, and could be cheaper if the shop has scrap from previous installations. so with parts and labor it is going to be cheaper than having a mechanic do it for you, and more reliable.