Loose Connections: A wiggle test is used to indicate if there is a poor connection in a plug, component, or wire included in a circuit. In this illustration the technician is wiggle testing a MAF sensor, located on the air tube of an engine. The technician is wiggling the plug and wires while monitoring engine performance. A scan tool is monitored and any variations in engine performance are noted. The circuit is being diagnosed for an intermittent condition.
No matter what kind of circuit is being diagnosed, a loose connection will wreak havoc on its operation. This is true for all connections located throughout a vehicle. A flickering dome light could have a loose plug, wire, or bulb. Today's vehicles have hundreds of connectors, and any loose connection will result in intermittent or no operation. These problems are often found during an initial inspection.
Loose wires and spaded connectors can be repaired by installing a new female and/or male connector. Depending on the manufacturer, the connector may be pinched or soldered to the wire and then installed back into the plug. Connectors are usually plastic, and a damaged plug or worn clip requires a new plug that matches the components connector to be installed.