Part Indentification????

Can someone tell me what this is and what this does? It is attached to the positive battery led and to a silenoid. It is on a 2003 Freightliner Forest River RV. I have been to an RV place and a parts store. No one was able to help. I think because it is a Mercedes. I broke it when replacing the battery. It was attached to the side fender wall. Made of plastic.

kris-nilsson,
Sure looks like an auto reset circuit breaker to me.
The big set of connections a little ways back toward the firewall looks like the junction point
where the starting battery in your photo below the broken circuit breaker) ties in with the
house battery.
Roger

There are no part numbers on it?

Kind of a hokey way of hooking things up, but I guess if it works...

it is not Mercedes Benz part!!!

It may have been a power diode, used to isolate the engine battery from the house battery. You can find these in many auto parts stores, as well as online catalogs. It would prevent current from being sent to your auto battery from some other charging system, will still aloowing your Sprinters alternator to provide some level of charge to your house batteries (altho you lose 0.7V as a result of the Diode's voltage drop, so the running engine often won't charge very fast or completely).

You can check it with an ohm meter - if it conducts one way but not the other, its a diode.

That makes sense that it is a circuit breaker. I removed part and it was stamped "Shortstop 12V K39 50A" and at the terminals are labelled "Aux" and "bat". However it is hooked "aux" to engine battery and "bat" is connected to the junction box. I tested it on a multi-meter and it seems to work.