Re: Overcharging Alternator (Delco 3 wire hook up)
If those 2 small wires are reversed it could very well be the reason it's overcharging.
Make it easy on yourself - don't trust the PO, his wiring, or his wire colors.
Get a new connector from the parts house - with short wires already attached - about $4?
On that connector you'll find a red wire and either a white or brown wire.
The red wire is the sense line. I honestly don't remember if it's #1 or #2 or A or B.
Run the red wire direct to the battery, not to the output of the alternator, and not spliced into the output wire. Make a new separate wire directly to the battery (+) terminal. That's very important if you want it to charge properly.
That's the "sense" line that determines if, and how much the battery needs to be charged. Running it anywhere else is just fooling - lying - to the regulator.
The other wire, usually white, but sometimes brown, goes to the idiot light. If you don't have a light, you need to go to a Radio Shack, get a 10 or 15 Ohm, 1 Watt resistor and a 10 amp Diode.
Wire it from that white (or brown) wire on the new connector to the diode - put that wire on the "cathode" or stripe end.
Put the other end of the diode to the resistor.
Put the other end of the resistor to IGN (+).
That wire energizes the field in the alternator. Without it the alternator has trouble getting started charging. The diode prevents it from backfeeding the ignition - making it impossible to shut the engine off.
Sounds like you have those two wires reversed right now - the "sense" line isn't "seeing" enough voltage, causing the regulator to "think" the battery is undercharged. It "tells" the alternator to go "full blast."
The battery won't last long being overcharged.
I really doubt you've damaged anything -- yet.
Shouldn't be a major task - even in the cold.
Let us know how it turns out.