Because of the increased demands a winch and other accessories place on the DC power supply, many vehicles have multiple batteries-one to start the engine and another to power accessories.

The WARN battery isolator prevents the problem of multi-battery drain. So no matter how drained your accessory battery becomes, it will never drain power from the battery you're depending on to start your engine.
GM Isolator Connector Kit. Required item when installing the PN 22630 isolator on '86 and newer GM applications.