Powermaster Ford 3G Style Alternators are internally regulated and have excellent output at idle. 3G Style Alternators feature dual internal fans for high efficiency and excellent cooling. 3G Style offer 3 options OE only, 1 wire only, or adapter harness. Function of adapter harness is to run a dash light or turn the alternator on with the ignition if equipped with a voltmeter. Replaces external regulator.