Jumper Wires

Jumper wires allow "jumping" across a suspected open or break in a circuit.
^ If the circuit works properly with the jumper wire in place, but does not work when the jumper wire is removed, the circuit has an open spot.
^ A circuit without any opens or breaks has continuity and needs no further testing.

The jumper is usually a long wire with alligator clips. A version of the jumper has a fuse holder in it with a 10-amp fuse. This will prevent damaging the circuit if the jumper is connected in the wrong way.

The jumper is used to locate opens in a circuit. One end of the jumper is attached to a voltage source and the other end is attached to the load in the circuit, i.e. lamps or motors. If the load works, try "jumping" to circuit points that are progressively closer to the voltage supply. When the circuit load stops working, the open has been located.

The jumper is also used to test components in the circuit such as connectors, switches and suspected high resistance points.