i usually check regulators by connecting their input to a variable power supply and a voltmeter to its output. start the power supply at 5v and keep turning the voltage up. this voltage should be passed onto the regilator output (and on the VOM). when the power supply reaches 14.4 volts, the regilator should cut out and the VOM should read 0.00

if it does not cut out then the regulator is knackered