[fleetsidelarry]

Jonathan-m, one trick I use is a short jumper wire to supply power to each curcuit I want to test. Often this doesn't have to be anything fancier than a short piece of wire with the ends stripped (although a better way is to use an in-line fuse holder).

the brown wire for the tail lights should have nothing to do with turn signal curcuit and they should come on as soon as the knob is pulled one notch out, and should stay on when you pull to the headlight -on position.

try this quick test, unplug the light switch and jump between the red and the brown. this by-passes the switch and tells you if you have broken wire (not at uncommon) in the tail light curcuit, or a bad connection at the firewall plug (also, not uncommon)

I thinkthat my switch works out of the dash. the only light that this switch operates that isn't self-grounded may be the dome light, and it could be that the green wire that runs to the fuse panel is the ground for that lamp, but I don't know that for sure

it bothers me that your dome light blows a fuse, you may have wiring issues further into the harness, but do the simple jumper test first to eliminate the HL switch.