I just bought an a/f and boost gauge with indiglo lit backface and before i just tear into the dash i was wondering if anyone knew the best and easiet place to tap into the dash light powersource so the guages will light up when my dash lights are on.

Use the dimmer switch. Thats is what I would do. But if you wanna go another route, here is a diagram of the instrument panel illumination.

also the 12v power source thats only hot when keys on for the a/f gauge, i was figuring the fuseblock but wasnt sure if there was an empty spot or which circuit i could tap into without causing problems.

thats what I did. I don't remember which one I tapped into, but I am pretty sure you a/f gauge is not gonna pull enough amps to hurt any of them. But just choose something none vital just in case. I mean hell, better that the fuse blows for the radio than your wipers on a day it is pouring rain. :lol:

Yea I didnt think about the radio circuit, I dont guess it would hurt anything to put the gauge on an accessory circuit, I doubt itll run the battery down much faster if Im just sittin and listening to the radio