Yes you need to add a resistor or light or both to the "L" terminal wire. By 4.3 alt. is wired the same.
I went to radio shack and got a small light and a 10 ohm resistor. Mounted the light at the dash.
Wire it by putting switched ignition power to the light, out of the light to the resistor, out of the resistor to the "L" terminal.
Turn on the ignition switch and the light will come on. Cranking the engine will cause the alternator to ground the "L" terminal when if starts charging and the light will go out.
This way you know out on the trail if your alt. stops charging because the light will come on. Just like GM designed it.
Note the resistor may not be needed it the light you choose has more than 10 ohms of resistance.
This can also be done with all the wiring at the engine. Finding the switched power and putting the resistor and light at the alt. If you don't need a alt. charging indicator at the dash.
Pop the hood and see the light on =bad alt.
(http://www.pirate4x4.com/tech/billavista/Wiring/Part2/#csseries)
