Small Engine Troubleshooting Problems? Ask a Mechanic Now.
I see you have had no reply! Do you have a voltmeter to test the battery voltages?
Flashing light is low voltage. Can be from bad battery or connection. Or charger can be bad.
Charger will not work, if battery or connections are bad. Check each battery and the total battery pack voltage. I assume this is 24 volt unit, so if battery pack reads 24 volts, the charger is at fault.