1) From everything I have seen the BIM has nothing to do w/ CONVERTER charging HOUSE BATTERY, it should do that even if BIM bad? The BIM determines if the engine charges HOUSE, or lets CONVERTER charge CHASSIS if needed. 2) CONVERTER (I.e. GEN/ or shoreline) should charge coach even if BIM bad. 3) Alternator should charge Chassis batterY even if BIM Bad. BIM controls a CHARGE SOLENOID THAT connects COACH BATTERY to CHASSIS BATTERY, and BAD solenoid can CLUNK and still not connect. REPLACE Charge SOLENOID w/ a CONTINUOUS DUTY type. If GEN NOT charging COACH, then check CONVERTER AND REVERSE POLARITY FUSES AND 12VDC CIRCUIT BREAKERS NEAR BATTERY (on battery end of CONVERTER CABLE). HOPE THIS HELPS.