Converter Switching Problem

Barry asks:

I just purchased a 1984 Fleetwood Southwind. 27'. I ran the generator for the first time today. About 2-1/2 hours. Everything worked fine.
Prior to running it, all of my interior coach lights worked fine running off of the coach battery or when I hooked to shore power. I shut down the generator, and the interior lights went out. I checked everywhere for a breaker or fuse, but none were blown. I decided to fire up the
generator again, and the lights came back on. Is there some relay or switch somewhere that would turn it back over to battery power? Or should it be automatic and there is a possible problem with the relay? This is quite perplexing. Any help would be greatly appreciated.

Thanks in advance!

Hi Barry,

You most likely have the Magna-Tech converter in that coach, and yes indeed there is an automatic relay that switches from battery to converter power. When you plug into shore power or run the genset, the relay pulls a switch closed that disconnects the battery and connects the converter output to the 12 volt system. When you unplug or shut down the genset, a spring then pulls the relay back to the battery position.

Sometimes corrosion builds up on the contact points and insufficient contact is made. Usually cleaning the contact points fixes this common problem with these converters and it is not a difficult repair to do.

Step by step instructions:

1. Make sure your coach is disconnected from any source of 110-volt electrical power including the generator and shore power.
2. Disconnect the on board 12-volt battery.
3. You need to have access to the four converter cover screws (one on each lower corner) – you may have to remove the converter from beneath cabinets or other obstructions.
4. Remove the screws and lift off the cover. The switch over relay is about 2" by 2" in size with various wires connected to it.
5. The relay has two sets of contact points, one over the other. These contacts have a rounded surface and a file should not be used on them. Instead, insert a business card or similar piece of stiff paper between the points and pull it back and forth to remove the contaminants. It helps to use a cleaning solvent or alcohol on the card. Be sure not to leave any of the card material on the point surface.
6. If the contact points are burned or pitted, the relay will have to be replaced, as cleaning will not likely improve its operation.