Hello,
I'm new to the forum but I did a cursory search for this and didn't find anything to help. I appologize in advance for the length of this post but I want to fully explain my problem.
I have a 25' 97 Coachmen Class C on a Ford E350 chassis. Just before my last trip, I noticed that my fridge would not run when on battery power. I got a very faint "auto" light on the fridge but it wouldn't get cold and none of my DC lights would work. I have a Battery disconnect switch and that would light faintly but it would not "switch" i.e. it would not disconnect - the light would just stay on faintly. If I plugged in 120, everything worked fine. The fridge would come on, the DC lights would work and the battery disconnect switch would turn everything on or off as expected.
I checked the battery and it seemed to have a charge but the cells were low on water. I bought another battery anyway and tried it but still had the same problem. I limped along with the generator and shore power when available.
So I've been trying to figure out what is wrong by poking around with the VOM. The battery sits in a box under the inside step. The ground goes to the frame and after some serious scraping, I measured 12 V from the positive terminal to the frame so I think my ground is OK. The Plus wire however, makes a rather complicated journey that I hope you guys can help me with.
From the battery terminal it makes a short run to what looks like kind of a power distribution "panel" although panel is too kind. It first goes to a terminal which appears to just be a place to make another connection to what I assume is an isolator. The connection between this terminal and the isolator is via a strange, flat piece of metal with a square object in the middle. I'm guessing that this is some kind of fuse???? There are two large terminals on the "isolator" (I'll call it an isolator but I'm not really sure). On the same terminal that the battery connects to (via the "fuse") there is another fairly thick wire. On the other terminal of the isoloator is another fairly thick wire. I'm guessing that one of these is from the converter and one is from the truck battery but I'm not clear which one is which. I know that the isolator keeps the house load from draining the truck battery but I don't really understand how the converter DC power fits in with everything. Would the converter POS be on the same terminal of the isolator as the battery Plus?There is also a small black wire that connects to the base of the isolator. Is that the emergency start line that connects the house battery to the truck battery for extra starting power?
Anyway, I was trying to follow voltage from the Pos battery through the wires of the isolator and getting nothing. Everything was so rusted and corroded that I could not get any readings. I first tried to take the battery cable off that first terminal and proceeded to break the bolt off - great! I tried removing the cables from the isolator and they were also rusted on. I basically ended up destroying the isolator in an effort to remove the cables.
Soooo, first, do the symptoms sound like a problem with the isolator? Are my assumptions about connections correct? Any suggestions on where to get another isolator?
Thanks for any help,
Tom
I'm new to the forum but I did a cursory search for this and didn't find anything to help. I appologize in advance for the length of this post but I want to fully explain my problem.
I have a 25' 97 Coachmen Class C on a Ford E350 chassis. Just before my last trip, I noticed that my fridge would not run when on battery power. I got a very faint "auto" light on the fridge but it wouldn't get cold and none of my DC lights would work. I have a Battery disconnect switch and that would light faintly but it would not "switch" i.e. it would not disconnect - the light would just stay on faintly. If I plugged in 120, everything worked fine. The fridge would come on, the DC lights would work and the battery disconnect switch would turn everything on or off as expected.
I checked the battery and it seemed to have a charge but the cells were low on water. I bought another battery anyway and tried it but still had the same problem. I limped along with the generator and shore power when available.
So I've been trying to figure out what is wrong by poking around with the VOM. The battery sits in a box under the inside step. The ground goes to the frame and after some serious scraping, I measured 12 V from the positive terminal to the frame so I think my ground is OK. The Plus wire however, makes a rather complicated journey that I hope you guys can help me with.
From the battery terminal it makes a short run to what looks like kind of a power distribution "panel" although panel is too kind. It first goes to a terminal which appears to just be a place to make another connection to what I assume is an isolator. The connection between this terminal and the isolator is via a strange, flat piece of metal with a square object in the middle. I'm guessing that this is some kind of fuse???? There are two large terminals on the "isolator" (I'll call it an isolator but I'm not really sure). On the same terminal that the battery connects to (via the "fuse") there is another fairly thick wire. On the other terminal of the isoloator is another fairly thick wire. I'm guessing that one of these is from the converter and one is from the truck battery but I'm not clear which one is which. I know that the isolator keeps the house load from draining the truck battery but I don't really understand how the converter DC power fits in with everything. Would the converter POS be on the same terminal of the isolator as the battery Plus?There is also a small black wire that connects to the base of the isolator. Is that the emergency start line that connects the house battery to the truck battery for extra starting power?
Anyway, I was trying to follow voltage from the Pos battery through the wires of the isolator and getting nothing. Everything was so rusted and corroded that I could not get any readings. I first tried to take the battery cable off that first terminal and proceeded to break the bolt off - great! I tried removing the cables from the isolator and they were also rusted on. I basically ended up destroying the isolator in an effort to remove the cables.
Soooo, first, do the symptoms sound like a problem with the isolator? Are my assumptions about connections correct? Any suggestions on where to get another isolator?
Thanks for any help,
Tom