New to posting but have been using all of the knowledge posted on the threads with a lot of success until now. I have read a lot of the alternator threads and I have done all of the trouble shooting items listed but I still can't get my alternator to charge the battery. I swapped a 87 V8 fuel injected 305 into an international scout. I get the following reading for the alternator wires with the key in the run position. Red wire 12.04 volts, brown and tan wire 12.04 volts, brown wire 11.98 volts. The battery reading is 12.14. I realize that the brown wire is lower because I put the 470 ohm resistor in the circuit. I did this because the original car had the resistor in the circuit board. The alternator is new and been test by two different shops (passed at both). The battery is new as well. I have tried different batteries with the same results. With the truck running the battery drops to 11.83 volts. The all the I have tried is a new connector but any other suggestions are appreciated.

 

470 ohms might be too many-could try a small light bulb such as #168 instead of the resistor.What alternator is used-87 could be 12SI or CS130 depending on the vehicle engine came from.

 

It is a cs130. The factory manual that I have said you can use either the 470 ohm resistor or a light. I will try a light and let you know what happens. I hope it is something as simple as too much resistance.

 

That should be 47.0 ohm =, as in 47 ohm, not 470 ohm. Also best to use a 1 watt resistor but that's hard to find in the 47 ohm size.

Simple wiring on the CS130 is
S terminal wire on plug goes back to output stud/post on alt.
L terminal wire on plug goes to switch 12 volts or warning light/voltage gauge. If used just on switched 12 volt source, you need a 47 ohm resistor inline.
Other wire not used.

Post on back of alt, run 10 ga. min (I like to use 8ga.) wire from there to battery + or starter main 12 volt battery post.

I have done many this away and all works great.