Checking For Short Circuit to Ground
Checking the circuit as shown will detect circuit faults that are providing an unintended current flow path to ground. The examples illustrate two methods of troubleshooting a short to ground that is causing a blown fuse in the circuit powering the license plate lights and the glove compartment light.
Using an Ohmmeter (Multimeter)
Step 1 - Remove the fuse
Step 2 - Disconnect the load (powered components) to eliminate the circuit's normal path to ground
CAUTION: Always use a digital (low current) meter. An ohmmeter, or the ohms scale of a multimeter, measures resistance by passing a small amount of current through the circuit or component being checked. Improper testing may damage sensitive electronic components.
Continuity (approximately 0 Ohms): Little or no resistance indicates that there is a continuous conductive path between the isolated circuit and ground, even though all the circuit's normal ground paths are eliminated. There is a short-an unintentional connection to ground-somewhere in the circuit.
NO Continuity: The circuit's normal ground paths have been disconnected, and there is no other connection between the isolated circuit and ground-no short has been detected.
CAUTION: Direct contact with meter probes at the connector terminals can easily damage the small contacts, causing poor connections and risking future intermittent faults.
Audi Special Tools include adapters for making test connections safely and preventing connector damage. Tools and Equipment
Using an LED Test Light or Voltmeter (Multi meter)
Step 1 - Remove the fuse
Step 2 - Disconnect the load (powered components) to eliminate the circuit's normal path to ground
Voltage: If the test light or multi meter indicates voltage, then there is a complete circuit-a connection to ground even though all the circuit's Normal ground paths are eliminated. There is a short-an unintentional connection to ground-somewhere in the circuit.
NO Voltage: There is not a complete circuit. The circuit's normal ground paths have been disconnected, and there is no other connection between the isolated circuit and ground-no short has been detected.
CAUTION: Direct contact with meter probes at the connector terminals can easily damage the small contacts, causing poor connections and risking future intermittent faults.
Audi Special Tools include adapters for making test connections safely and preventing connector damage. Tools and Equipment