I don't have anything to see what fuses are powered when the vehicle is on/off, or the voltage. I'm installing a dash cam and want to tap into a fuse that is powered with 12v only when the key is turned.

First thought was to tap into the cig lighter fuse but it seems like it has constant power. Hopefully someone has a good idea of what to tap in to.

 

you should just go and get a test light. it will make your life so much easier. and yes, the cigarette lighter and power ports are live 24/7 key on or off.

 

You also want to consider the combined draw of your dashcam unit plus whatever the fuse you're linking into already draws. In the past, I've added additional lights and such to vehicles I've owned, and what I'd do is run an oversized fuse in the box, then I'd cut the wire to the regular lights, put in an inline fuse of the appropriate amperage, and do the same for the additional lights I'd mount.

 

i hardwired my radar detector, i got a mini fuse splitter from pepboys (4 or 5 bucks), and used the rear wiper. i figured if it were to ever blow i wouldnt be in bad shape. also the splitter was said to run in parallel, meaning if the wiper fuse blew, the camera in your case would still turn on if the blazer was on