Charging problems .... Please HELP !!!!

I have a 1987 Ranger STX. Recently, after driving through the cold weather we've been having, my battery kept cutting out on me so I had to go to the Auto Zone in my town to have them run a check on my battery. They did and said the battery was dead & I had to buy another one. So I did. The guy there was so screwed up! I should have guessed it when he got in my truck and asked how to put it in PARK! (It's a 5-speed manual) Anyway, I bought the battery and due to my lack of tools on me~ I had to have him take out the other battery and put in a new one.... simple job, right? .... Wrong. He couldn't figure out the size wrench he needed to remove the cables. After several tries and trips in and out of the store without any luck, I located the 1/2" wrench and removed the cables. I think he was embarrassed that a GIRL knew more than him. Then to make matters worse... he put the battery in and attached the positive cable. Then he proceeded the attach the negative cable..... Repeatedly it sparked fiercely in the engine. He kept taking the negative off saying something was grounding out on the engine. He tried several times to put it on... each time it sparking worse than the last. Then he had an idea to force it to stay on suppossedly to pass the spark. But then my started relay started sparking and smoking and he couldn't remove the positive cable fast enough (lots of smoke). He said he couldn't put the battery in until the ground was fixed and there was nothing he could do. Frustrated I called my husband who came up there and immediately reconized that the guy was installing the battery BACKWARDS....Positive on Negative, Negative on Positive.... I can't believe I didn't catch that one! My husband got a new battery and starter relay and thought it was done so he left. I wanted to make sure everything was still OK so I had them perform another check. But then my battery light was on, which it had never been on before. He said because he was checking it. Checked ok according to him! But since my battery light was still on and by this point I didn't trust him, I went into Murray's to have it tested. They said the alternator was overcharging at 16.3 / 16.9 and then after bringing it home the truck died and won't start without a jump....and the battery light is STILL on when it starts.... I guess what I am now wondering is .... Could the battery being installed backwards cause the Diodes to go bad on the alternator itself, as I have been suggested? What would your opinion be? Thanks.... Karen

I am not too much of an eletronics person, I am not sure what diodes actually do. My bother got my dads electronic mind, and I don't know what happened with me, I am good with making things out of metals and developing software.

It sounds like the voltage regulator is toast. Probably will need a new alternator. I am suprised the battery didn't screw something else up being put in backwards. I've heard of trucks never running again after that. It's easy to do in a Ranger if you don't pay attention. I think by default people tend to put the batteries in, posts closest to the terminals. After rebuilding my engine I almost found my self screwing up like that.

One thing I've learned in life so far: NEVER, under any circumstances, let another person work on your vehicle. Espically a grade A idoit from Auto Zone. My friend had his oil changed in his 1979 ford fairmont station wagon. They didn't tighten the oil plug bolt all the way and it start knocking out in the boone docks. Luckily we had it towed and no real bad damage was done to the motor. I could go on all day about people getting bad repair work done. It's nuts, I don't know how people screw up some the of the simplest things. They'll never blame it on themselves either, let alone apologize for their mistake. It's always your fault.

Its entirely possible for that to happen. Putting a battery on backwards can do numbers to your vehicle. Best thing to do is buy a new aleternator. It should only run you about 140 or so and its such a simple fix. If that dosen't work then i don't know, sounds like another case of the Autozone Dumbasses.

Well, I wanted to thank you for replying to this....

The voltage regulator (or diodes as I understand it) is built into the alternator in this particular model. Apparently, that was the problem and after arguing the point with the manager and then onto the district manager, we managed to get them to take care of the cost of the alternator all together.

They had to replace the starter relay and alternator due to the battery being placed in backwards. The alternator had drained the new battery in less than a day. But all the parts were replaced and it's back up and running again!

Thanks for the input...
Karen