Your directional and your hazards are on different circuits and also have different modules to make them "blink". Check your owners manual for the location of both the fuses and the modules.
The blinker is on a separate fuse from the hazard lights. You probably need a fuse just for your directionals. It is located right next to the fuse for the hazards.
The two first things to check are the fuse and the blinker capacitor. Both can be replaced very inexpensively.
replace fuse and hazard flasher
The flasher relay is in the hazard switch. The hazards work on my wife's S4 but the directionals don't. I found another posting that says that the relay is in the hazard switch. The fuse is fine.
There are two flashers, one for the hazards and one for the signals.
Because it is an American made car.
Broken bulb, or the wiring is shot.
the hazard switch has two sets of contacts. when hazards turned on, blinkers cannot work,even if hazards dont work.for blinkers to work, hazard sw must be in off position-this reconnects blinker circuits to work normally. BUT-the contacts in the hazard sw get dirty and wont reconnect the blinkers to work
most likely that would be a fuse
Either the switch is bad or the relay is.
Some will, some wont. You need to ask a new more specific question about a certain part.
There are two different flashers on vehicles. 1 for the turn signals, 1 for the hazard flashers.