First check all wiring & connections by hand making sure everything is tight & secure including all ground cables & wires, free from rust & corrosion, switches, relays, bare wires, wires chafing chassis, etc. Check for low battery voltage, loose wires or poor ground to the voltage sensor, or defective voltage sensor. You can remove battery & take to auto parts store & have them load test battery with machine for no charge. Let us know how it goes, thanks.