You went to change out the stereo in your 2003 tacoma and somehow when messing with the dimmer wires on the stereo you have no dash lights and your tail lights fuses are blowing when theyre messed wit?

I'm not sure if this is the same but the ground wire going to the stereo is not really ground! Try running the hot wires for your new stereo right to the fuse box or straight to the bat and see if that cures it. I had a problem that was very similar but it wasn't a Tacoma.