⚡ Do you want to be a successful electrician? Check out my complete training. Click here ???????? https://www.eunaupmotors.com.br/eletr... --------------------------------------------------------------------------------------- The small and harmless fuse is an extremely important component for the safety of the car's electrical diagram because a poorly sized fuse or its absence allows a short circuit to cause a lot of damage to both the wiring and the electrical components of the car. All cars have individual protection fuses for each electrical component, in rare cases a fuse protects more than one component. The testing procedure is relatively simple but it is necessary to interpret the signals collected by the test tool to make a good diagnosis. To be able to provide protection, each fuse has 2 thicker contact points that are connected to the wiring and joining these 2 contact points there is a metal filament that supports only the amount of amps that are described in the fuse and when this value is exceeded then this filament will break or burn, preventing the passage of energy in the circuit. Now that we know the real function of the fuse and how it works, let's take a look at the testing tools to find out when a fuse is blown: the first and most commonly used is the polarity test pen, which has 2 LEDs, one red that turns on when we touch the test tip to a point with a positive signal and the other green that turns on when we touch the test tip to a point with a negative signal. I recommend using the test pen with LED to test the fuses because the test pen with a bulb has a high energy consumption and can cause problems if it is connected to a fuse that does not support this energy consumption, causing unnecessary rework. When looking at a fuse, we immediately notice that it has 2 metal points on its most visible upper part and these are exactly for testing. Never remove the fuses to do a visual analysis to see if it is blown because certain fuses supply components that need energy to store operating memories, such as an original radio that needs a code to work or the electronic injection control unit that stores engine operation data. Therefore, the correct way to test the fuses is through these metal points. To perform the test, we must first turn on the vehicle's ignition and connect the component we want to test. For example, if you want to test the headlight fuse, turn on the headlight. When you touch the test lead to the 2 test points of each fuse, notice that some will turn on the green light on the pen and some will not turn on at all. In both cases, disregard this and continue testing the next fuses, as these are not what you are looking for. The other fuses will turn on the red LED on both sides of the fuse, which indicates that positive energy is flowing through them and the fuse is good. However, if a fuse turns on the red light on one side and nothing or the green light on the other, then this means that the fuse is blown, as if it is good, it will always have the same signal on both sides. Remove this fuse and replace another one that is the same. Another way to test is with the multimeter set to the 20Vdc scale. Touch the black tip of the multimeter to some unpainted metal point on the car to get a negative signal and with the red tip go to the test points of each fuse. Consider the 12V or approximate as the red light of the test pen and whenever the value is different in one of the fuse points then it is burned out and must be replaced with another one of the same. Remember that a well-sized fuse lasts forever so if it burned out it is because something is wrong in the car's electrical installation and needs to be checked. I hope I have clarified the fuse testing procedures and what their real function is. I'll stop here and wait for you with our next topic, thanks. Complete Courses, all in one place! I teach you with the best techniques of today, with my method that has already been tested and approved by more than 2,600 students in Brazil and other countries. ⚡ Successful Electrician. Click here ???????? https://www.eunaupmotors.com.br/eletr... ---------------------- ▶ SUBSCRIBE TO THE CHANNEL / upmotorscentrodeforma%c3%a7%c3%a3oautomotiva ---------------------- ????FOLLOW ME ↴ ▶ Facebook: / eunaupmotors ▶ Instagram: / eunaupmotors ▶ Telegram: https://t.me/Eletricista_UpMotors ▶ Website: https://www.eunaupmotors.com.br/