This should help. Int. alternators were the same as GM.
Wiring the Si series alternator.
Although they may vary in size and output the wiring is the same for all the Si series, wiring these alternators is quite simple.
All the Si alternators can be considered both 2 and 3 wire systems. To activate these alternators you are only required to
supply the main battery wire to the (BAT) terminal which must have power on and an ignition wire to the #1 terminal.
Most all the Si series alternators should have two spade terminals, but some that have three terminals, the third
is for a tach connection. Near the spade terminals the rear housing should be marked #1 & 2. Some aftermarket
housings are not marked and others may be worn off, so if yours is unmarked, looking from the rear of the alternator
the #1 terminal is on the left and the #2 on the right. As I said earlier you only need an ignition wire to the #1
terminal to make the Si alternator work. The #2 terminal is voltage sensing, this is an optional terminal. The #2 voltage sensing
terminal is for the voltage regulator to sense what voltage the battery is at so it knows when to turn the alternator on and off.
The reason the #2 terminal is optional is that if it is not used the regulator reverts to internal sensing and picks up the
battery voltage at the main battery wire on the back of the alternator. I've seen alternators wired with a jumper from the #2
terminal directly to the battery connection at the back of the alternators, this is not needed.
The ignition wire to the #1 terminal can be supplied in two ways, either a direct ignition wire from the key switch or through a
light bulb. Running the ignition wire through a light bulb before connection to the alternator will give you a warning if your alternator
fails to start charging or if it quits working while the engine is running, this is commonly known as the idiot light. Another thing that
should be mentioned is the #1 terminal must be ignition switched. I have heard of situations where a wire was run to the #1 terminal
that had power on at all times. What happens is when the engine is turned off the #1 terminal switches to ground which over time
can burn up the voltage regulator or the wire if power is not cut to the #1 terminal.
Another note for special installations of the Si series alternator is that in some cases when you try to shut the vehicle off it continues to run.
This is caused by the fact that once the alternator starts charging the voltage regulator switches the #1 terminal from ground to positive power, the plus power feads up to the coil and keeps the vehicle running.
To cure this you must install a diode in the ignition wire that activates the #1 terminal. The diode will stop the power from feeding back up the ignition line.
