TECH TIP #101 – ALTERNATOR PROBLEMS?
Are you having alternator problems? When you check the charging voltage at the battery with the engine idling, you should see at least 13.5 volts. If not, check the wiring connections at the alternator – don’t just wiggle the wires or visually inspect them. Do an actual voltage drop test to check for excessive resistance. You might find that your “alternator problem” turns out to be a bad connection or a bad wiring harness.