Checking Ground Connections

Checking ground connections as shown confirms that the circuit is complete-that the necessary path to ground is uninterrupted and current can flow in the circuit. The example illustrates troubleshooting the high-speed circuit for the radiator cooling fan.

Voltage: If the test light or multimeter indicates voltage, then there is potential for current flow between the known voltage source and ground at the test point. The ground side of the circuit, between terminal 3 of the fan connector and battery negative (-), is OK.

NO Voltage: The test point is not providing a path that completes the circuit to ground. The fan is probably OK. Look for a fault somewhere in the wiring between the fan connector and chassis ground. Also check the mechanical ground connection at the chassis (body).







Continuity (approximately 0 Ohms): Little or no resistance indicates that there is a continuous conductive path between the two test points-the circuit's ground path between terminal 3 and battery negative (-) is OK.

NO Continuity: There is resistance to current flow in the ground side of the circuit. The fan is probably OK. Look for a fault somewhere in the wiring between the fan connector and chassis ground. Also check the mechanical ground connection at the chassis (body).


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