I've been messing around lately trying to install my tachometer....and now my dash lights no longer work...

i checked all the fuses. i actually know which fuse controls the dash lights, and put a test light up to it. when i turn the switch, the test light works. when the fuse is back in there, it doesn't work. ?? tried a different fuse and everything. tried different dash bulbs. nothing. i know it's drawing power, because the clock dims a bit when the switch is on.

it's my guess that the ground on that particular fuse block is shot somehow? to reinforce that theory....i added one of those "add a circuit" connections at that fuse block, and ran it to my illumination light on the tach. when i flip the switch for the lights, the tach lights up like a champ now......but the dash lights still remain off. but if you think about it, the tach has it's own ground......so it works. back to my original theory that the ground on that particular fuse block is maybe shot?

my only other guess is that the circuit is somehow fawked at the dimmer switch since i was messing around with that. i checked all my soldering, and everything looked good. i'm confused. another thing I might try is putting a jumper before the dimmer switch to see if that is actually shot. i don't see how it could be though. the design is ridiculously simple, and it looks like all the connections and contact points are working when you rotate the dial.

any ideas?