|From my FAQ: Testing Alternators.
If you don’t have 14 volts, you need to check a few other things. Most all alternators have a wire harness going to them. One of these wires is for the field voltage, if you don’t get power to the field, your alternator won’t charge. On newer YJs and all TJs, the voltage regulator is controlled by the ECM. On these alternators there are two wires on the back, one constantly cycles between 10-12 volts to control the alternators output, while the other is a reference wire to tell the ECM how much power the alternator is putting out.
95 YJ: SOA, locked 44, locked 8.8, 37s, beadlocks, OBA, winch, and a few other things. [URL=http://www.cdmfabrication.com/aboutmel.html]My Build-Up Post[/URL] -- [URL=http://www.cdmfabrication.com/kbl.html]SWB FAQ[/URL] -- Mike