New member. We’ve been having battery problems for several years. Replaced the starter, then the inverter(?) board in the cabin of the RV, then the alternator. Recently the ’87 sunrader would not start. An RV mechanic came to our house and said the cables were not connected correctly. He changed them, got the vehicle to start. But the next day the RV would not start again. Can you tell from these photos anything more? Is the item bordered in red my isolator? We see the solenoid is rusty, so we are replacing that. Help. My husband has a broken leg and can’t get out to the vehicle to assist the mechanic who will be arriving on Tuesday. I’d like to make sure he knows which is the isolator. IIRC, he didn’t seem to recognize the fixture bordered in red here. (I am a literature major, no knowledge of vehicles, but trying to learn.) Thank you in advance.