Checking Ground Connection

Ground Connection
Checking ground (GND) connections as shown confirms that the circuit is complete that the necessary path to ground (GND) is uninterrupted and current can flow in the circuit.
The examples illustrate two methods of troubleshooting a high-speed circuit for the radiator cooling fan. Testing with an ohmmeter and testing with a test light or voltmeter.

Testing With An LED Test Light Or Voltmeter (Multimeter)

Testing For Ground Connection:

Voltage:
If the test light or multimeter indicates Voltage, then there is potential for current flow between the known Voltage source and ground (GND) at the test point. The ground (GND) 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 (GND). The fan is probably OK. Look for a malfunction somewhere in the wiring between the fan connector and chassis ground (GND). Also check the mechanical ground connection at the chassis (body).

Testing With An Ohmmeter (Multimeter):

Testing For Ground Connection:

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

No Continuity:
There is resistance to current flow in the ground (GND) side of the circuit. The fan is probably OK. Look for a malfunction somewhere in the wiring between the fan connector and chassis ground (GND). Also check the mechanical ground (GND) 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 malfunctions.
Special Tools include adapters for making test connections safely and preventing connector damage. See Tools and Equipment.