Electrical Issues

[Death_Trap22]

So suddenly whenever i press the brake pedal the radio turns off and/or resets....then a week later the radio just doesnt come on anymore along with:
-brake lights(doesnt get brighter when i press pedal but does turn on)
-cig lighter
-interior lights
-door locks
-horn(when i press the horn the headlights turn off)

Any idea what could cause the problem ...no fuses are blown and the battery grounds seem to be in good contact.

I have no clue where to start....i do have wiring schematics and it looks like some of this stuff is tied together...where do i start...relays maybe?

Thanks...

 

[Death_Trap22]

Anyone,?

Just last night now the turning signals dont work....why?...are all the electrics dying....where do i start?