RV Repair: battery isolator, battery isolator, volt circuit

Question
When driving my coach battery will not charge. It will charge though when coach is plugged in or generator is running. I bought a new battery isolator thinking this was the problem. Still though when i remove the positive cable off the coach battery. I can start the generator and get power to the cable. also when i plug in the coach power to the cable. But still wont get power there when engine is running. Is there maybe a fuse or could it be i have a defective brand new battery isolator. Any help would sure be nice. Thank-you Greg.

Answer
Greg, First off I need to know what kind of coach we are talking about. Does it also have a battery disconnect? This coach may have a solenoid that engages when the engine starts. You should be able to check the isolator and see that there is power there when the engine is running. There might also be a 12 volt circuit breaker in line that may be bad. If this coach has them they should be pretty near the batteries. The main battery cable for the engine may go to something that also connects the batteries together. I could help you much more if I could get some more details from you. Thanks, Bill