This may be a very simple n stupid question but how do i use circuit tester. i saw some technitians use this , they tap it on the top of fuse n it lights up so i brought it. so how do i exactly use this... should the car be ON and i know that u crip that to postive terminal.... the wire from abttery to the device is short .... so if i wanna check the fuses that are IN the car, then where do i connect that hold on thing..
What I think you're trying to do is test the circuits running through the fuse box, not the fuses themselves. What you want to do is connect the clip end to a viable ground, which would be any good unpainted metal surface on the vehicle. Then you use the pointed end to touch to any place in a circuit that you want to test, in this case that would be the fuse box. If there is voltage running through that particular piece of the circuit you touched, it should run through the wire and light up the bulb inside of the circuit tester as it passes through the ground and makes a complete circuit.
So really, just clip anywhere that is solid metal on the car. Then use the point in the fuse box where you want to test the circuit.
such as your key in the ignition or a bolt that is screwed into the chasis or another metal part of your car negitive charge runs through your whole car thats called a your cars ground - any place that has negitive current going through it