Charlie,
The module in the diagram that Steve is referring to is called the BIRD-Battery Control Center (BIRD-BCC), it is located in the Rear Run Box. The BIRD-BCC controls the Big Boy relay and the 12-volt house disconnect relays (‘salesman switch’). The dash mounted START BOOST and BATT CUT-OFF switches are both connect to the BIRD-BCC.
There are two small yellow test buttons on the BIRD-BCC, one will energize the Isolation Relay (Big Boy Relay) and the other will cycle the two 12-volt disconnect relays. The test button for the Big Boy is labeled ‘ISO Relay SW’, pressing this button simulates pressing the START BOOST switch.
There is a green LED on the BIRD-BCC labeled ‘ISO Relay ON’ that will be illuminated when the BIRD-BCC is sending a signal to the Big Boy coil. This LED should be illuminated when connected to shore power and the inverter/charger is charging at least 13.3-volts.
There are also two 7.5-amp fuses on the board, one for the BIRD circuit and one for the BCC circuit.
While on shore power, if your house batteries ARE maintaining a charge but your chassis batteries ARE NOT, as Gerald mentioned, your BIRD system may be faulty.
You can use your Aladdin system to do some preliminary troubleshooting.
Connected to shore power with the inverter/charger charging at least 13.3-volts, turn the ignition key to the on position (engine not running) and compare ‘Battery’ voltage on the ‘Engine/Trans’ screen (chassis batteries) to the ‘House Bat’ voltage on the ‘Coach Electrical’ screen. Both should be at least 13.3-volts and should be within ~.5 volts of each other. If the chassis battery is reading less than the house battery your BIRD system is suspect, it could be a corroded Big Boy.
If you find that your BIRD system is suspect, you can try cycling the Big Boy relay with the START BOOST switch or the BIRD-BCC test button several times, this might temporarily clear any corrosion. This assumes that the Big Boy is engaging but not joining the two battery banks together. You will need to be disconnected from shore power, engine and generator off and the Big Boy initially disengaged.
I've attached an image of the Rear Run Box and the BIRD-BCC.
Scott