oh yeah the diagrams i was looking at didnt seem to show the hazzard switch at all. but it seems the power passes through it before going to the rest of the cicuits thats why you lose all the fuctions brake/hazzard/signal if the switch is bad.
as for the speakers? im not sure if all SHO's have...
I just bought a SHO with the same problem. I too was looking at the wiring diagram on a rainy night. my wife looks out the window and ta da my hazards are blinking away.i go out there and found it to be the hazard switch itsself. i originally had no brake lights(except the led's in the wing)/no...