The 94 has a 135a 3G alternator that should be able to produce well even with underdrive.
While there are several wires involved, the wiring is really simple. I just re-wired my 65 to accept one of these alternators.
If the alternator is really not the problem, the only thing other than a simple loose connection at the alternator, or something in the harness close by is the "I" signal that "tells" the alternator that the car is on and that it needs to get to work.
On some cars this is simply tied to the ignition switch and goes positive when the ignition switch is in position 2, or "run".
On other cars, this positive voltage is supplied THROUGH the idiot light in the instrument cluster. An intermittent connection at the bulb, or a flaky bulb can keep the alternator from operating.
This circuit is traditionally the cause of the most frustration with a non-producing, or intermittent alternator.
I am attaching a diagram of the connectors involved and a wiring diagram of a typical 3G setup. http://inlinethumb60.webshots.com/46...500x500Q85.jpg
The 3G has a "stud" on the back that is the "fused" charging line to the battery. This is fused in case the ALTERNATOR shorts out and provides a dead-short to ground for your battery. The charge line will glow red-hot and start a fire if your diodes short out and this fuse doesn't exist. This "battery" connection is usually one of the studs on the starter solenoid/relay.
Next, there is a 3-pin connector:
The "A" signal goes to a battery connection. Sometimes it is looped over to the charging "stud" on the back of the alternator, but usually it follows the charge lead to the stud on the starter relay.
The "S" signal simply loops over and connects to the single-pin connector labeled "S".
The "I" signal is the one mentioned above that receives a positive 12 volts to tell the Alternator that the car is on and that it needs to get to work.
Those are ALL of the connections needed for a 3G alternator to work!
Below is a wiring diagram that shows this pictorally. http://inlinethumb53.webshots.com/41...600x600Q85.jpg