I'm having an issue with my 2003 super duty 7.3l. I was driving down the road and my flipped my turn signal on and then pressed the brake, when I did that my turn signals stopped working.when I release the brake the turn signals work again but blink fast. So when I got home I looked under the hood to check the Relay and it was working fine, but when I hit the brake pedal they would stop working. So I walked to the back and found out my brake lights don't work either. Any ideas?

summary:
press brake pedal and turn signals stop working
brake lights do not work.

 

Do the brake lights flash when you have your Hazard Flasher on?

 

Start with the easy stuff first. Pull bulbs one at a time and see if it starts working. Could have a filiment broken and shorting the other system

 

the turn signals are normal until you use the brake pedal. Also your hazard lights don't work. Your left brake light stays on while hazard lights are on

 

okay I'll try that first. Thank you!

 

It could be the turn signal switch itself (The switch under the horn button/pad) inside the steering wheel if this happened without any other work being done. If that multi contact switch fails all kinds of weird stuff can happen with the brake, turn signal and tail lights.

 

okay. I changed the brake pedal switch and checked all the wires n such on the rear, that didn't work. Whats weird is when I press the brake, the turn signals don't work, but my backup sensors will beep and beep and beep. I can't understand why. Also when i hit my remote lock l, all. My. Lights will blink except the rear brake lights

 

You might look into the VSM (vehicle security module), it does some weird things when it goes bad. On mine (2002) when I open the drivers side door, the horn would honk and the head lights would come on. I don't remember what all the VSM controls but you could look it up here (do a search) or google it.