A lot of the systems you mention have control relays in them. if the voltage drops too low, they will toggle off and on as the voltage comes up. Kinda like a turn signal blinker. I would do a load test on the battery, and check the output voltage of the charging system with and without a load. If it drops below 13 volts with a moderate to high load, that's you problem.You ain't got enough juice Doc!!
