First step is to check your float charge voltage. It needs to be over 13.4 volts on the house batteries before a charge is sent to the chassis battery.
If lower then that, check what the battery temp sender is showing. You can just unplug it ( BTS on inverter ) also to test. Default is 77 degrees.
If all is well, Push the boost switch on and off while listening for the clunk.
That solenoid is most likely bad, be sure to replace with a contiounus duty type.