Got my 68 back from shop with new transmission in it and on way back home my buddy said no left brake or tail lights were on. I installed LED lights last year and they worked fine going to mechanics.
The mechanic did say that when he was working on car, that my starter shorted out for no reason? I don’t know if the two are related? I checked fuses under dash and they are fine.
I did the obvious wire checking in tail lights and nothing seemed unusual. I ordered and replaced the turn signal...

1968 Mustang tail lights out.