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.