Testing For Continuity/Shorting

Continuity/Open Circuit (Resistance measurement)

1 Make sure that the component or lead to be checked is not live.

2 With the instrument set to measure resistance, connect the test leads to each end of the component or lead to be checked.

In the wiring, the resistance should normally be less than 1 Ohm. The resistance of components should be that specified for them.

Continuity/Open Circuit (Voltage measurement)

1 Connect up the load, if any.

2 With the instrument set to measure voltage, connect the black test lead to a good ground and the red test lead to the wiring side.

3 At the output of a control module or switch: take readings in the direction away from them and proceed successively along the lead towards the load. When the voltage reading drops to zero you have just passed the break in continuity.

4 At the input of a control module or load: take readings from the power source and proceed successively along the lead towards the control module or load. When the voltage reading drops to zero you have just passed the break in continuity.

Shorting To Ground (Resistance measurement)

1 Make sure that the lead to be checked is not live and that the load, If any, is disconnected.

2 With the instrument set to measure resistance, connect one of the test leads to the load side of the electric lead and the other test lead to a good ground.

3 Carefully move the wiring about and observe the instrument at the same time to see whether it shows infinite resistance (OL) the whole time. (OL = Over Load.)