Voltage Regulator Troubleshoot

Thanks guys! Yes Miles, I have the Lestek, and my repairman told me to check the regulator after installation to make sure it was working properly, so he knew it wasn't built in. How do I test the voltage at alternator? I know both hot leads are to chassis & coach batteries. Do I just touch positive lead to those(one at a time), and the ground to ground(or to one of the small terminals)? At initial startup, the gauge showed 10volts, and when I turned on headlights it dropped to 8-9volts.(if that tells anybody something).