It should be that a circuit remains closed and operational if it has continuity. In fact, a continuity check for electrical and electronic wires and components is recommended in all service manuals. This kind of diagnosis is done in order to see if the electrical circuit is completely closed and has no opens.
Just so you know, the continuity check is generally conducted in the following fashion. First, the range selector is set to the highest resistance range possible. Then the multi-meter test leads are connected to the opposite ends of the electrical or electronic wire or component being tested. Finally, the technician reads the multi-meter. If the reading shows zero, then it means that there’s continuity. Alternatively if it shows infinite reading, then there’s an open circuit. Again, this is not to encourage you to do the test or reading on your own. Instead, this is to give you awareness of how the procedure is done.
Auto electrical technicians working in collision repair shops usually make use of two main methods to test electrical circuits. First is by using a simple 12-volt test light, and second is with the use of a multi-meter.
The 12-volt test light is device composed of a sharp probe, a ground wire with alligator clip and a 12-volt light bulb. The technician uses this by touching the probe to a positively charged electrical component and the other to a negative battery post. The presence of power in the circuit is determined by the light bulb turning on or not.
Although the 12-volt test light is effective, many collision repair shops make use of a multi-meter. This is because there are far more many uses for this device than the regular 12-volt test light. In fact, car manufacturers recommend the use of a multi-meter because it is designed in such a way that it doesn’t cause any damage to the delicate electrical components of the vehicle.