Yes, push the boost switch and see if the battery volts of house and chassis even out.
If not, push that switch on and off while someone listens for the solenoid clunking.
That solenoid is the same one that creates the connection between the chassis battery and the house batteries.
If it has house batt volts on one side and chassis batt volt on the other, even if it clunks, with the boost switch held, its bad.
If it don't clunk, follow the small wires to a control box or circuit and look for a fuse. That would be the brains of your BIRD or IRD.