What does a 12-volt reading across a connector indicate with power on?

A 12-volt reading across a connector with power on indicates that there is voltage present at the connector, which suggests that the circuit is complete and functioning properly. This means that the connector is good, as it is allowing voltage to pass through, confirming that the circuit path is intact and that there is no open circuit or shorts occurring.

In a well-functioning electrical system, you would expect to see a voltage reading close to the system's nominal voltage (in this case, 12 volts in a typical automotive electrical system). This implies that the connection is solid and that current can flow freely. Therefore, when you measure a 12-volt reading, it affirms that the connector is in good working condition.

If the connector were open, you would not observe any voltage, as an open circuit would prevent electrical current from flowing. A reading indicating a short circuit would typically display a voltage drop or an excessively low reading due to the unintended connection between wires. Reverse polarity would manifest as a reading of negative voltage, indicating that the positive and negative connections are swapped. Thus, a 12-volt reading confirms that the connector is functioning properly.