>Do I have to upgrade my alternator on the 1990 100 ? When I use AC and >high beams my voltmeter shows exactly 12 volts. What would happen with >AC and the 100W high beams ??? I'm running the Stock 90 amp alt. and I don't have a prollum. Check the voltage at the battery and at the Alt. the drop should be no more that .2 volt. Later! Eric Fletcher '87 5KCSTQIA2RSR2B STEADI RIC@aol.com