/diy/ - Do It Yourself

>>1639681
Shit pic didn’t even have the Power Probe in it.

If you’re a shadetree mechanic by any stretch, it might be worth grabbing one since the basic model is only $60 and it’s so much faster to check connections and wiring than other methods. Works great for testing fuses too and should be logic safe unlike cheap test lights (basically those cheap test lights pull power through whatever circuit you test, so if you’re testing power on sensitive low current stuff, you can pull too much power through it and fry the thing you’re testing).

You gotta understand DC electricity and relays and fuses a little bit for cars. Understand that cars are negative ground, which means the frame is all grounded meaning basically any bare metal on the frame and body is connected to the black (-) post on the battery. So if you want to power something, you run the red (+) wire through a switch (and often a relay) + fuse, into the + of whatever device, and then the - wire of the device will be grounded to the frame. So when playing with electricity in cars, if you have a red wire with 12V + running through it, don’t just let the thing hang around touching bare metal or you will get a short circuit and some sparks-heat and maybe fire.

Read up on relays, you don’t want to run lots of power through switches for lots of reasons so the switch to turn something on/off actually sends power to a relay, just enough to activate the little magnet in a relay (as opposed to the power needed for bright headlight bulbs which is much more) and the relay acts like a switch for the higher current going to a power hungry device like headlights or horns or starter. Having lower power running through the switch means you don’t have to run thick ass wire from the battery all the way to the switch in the cabin and back down to the device in the engine bay.