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hey whats up i just bought a new alternator for my 1988 mazda 626. i have it mounted and now all i need to do is connect some wires. there was the B terminal and a plug originally. the plug had two wires going from it but the guy who replaced the last alternator ghetto-rigged it cus he busted the plug. what he did was run one wire (white/green) to one diode, and another wire (black) to another diode. the problem is that i dont know what wire goes to which diode. if anybody knows which wire goes to which diode or if it will cause damagage to the lternator if the wires are crossed please let me know. i apprecaite any advice. thank you
 

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If I were you I'd go to a near by junk yard and get a plug with plenty of wires and attach that to the existing wires right with either crimp connectors or solder it with shrink tubes making sure it's clean and water tight... that would ensure no future problems, plus then all you'd have to worry about is matching the correct colors of the wires.

Just my 2¢

I think I remember someone having scans of the wiring diagrams in their sig? I wish I could remember who... I'd look it up for you but my book is conveniently 30 miles away.

-Todd
 

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The two smaller terminals on the alternator are labeled "S" and "L". "S" stands for "Sense" - this is the white/green wire that is connected to the battery to sense the actual battery voltage. The "L" stands for "Light" - this is the smaller solid black wire connected in series with the CHARGE light in your dash, its purpose is to provide the initial field current for the rotor in the alternator so it can begin generating voltage after you start the engine. There's a diode in the alternator that turns this light off once the alternator starts generating voltage higher than the battery.

I'm curious which diodes the previous owner hooked the wires up to - were these diodes inside the alternator? That would make sense since the L and S terminals do connect to both a diode that is part of the internal voltage regulator (white/green), as well as a diode that is part of the rectifier (black).

In case you're curious, the alternator's internal regulator does not just sense the voltage at the big "B" terminal ("Battery") because the output of the alternator effects the voltage reading - measuring it through a separate terminal as Mazda did gives better regulation where it counts.
 
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