My blinker used to work off and on, but now they just dont work at all...
I was teaching my girlfriend how to wiggle the battery cables, and when
she slammed the hood they started working for a couple of seconds then
stopped.

 

Presuming you have a Hyundai, try cycling the hazard switch and rechecking
the blinkers. If that causes the blinkers to work, you need a new hazard
switch. If not, it could be either the hazard switch or the blinker
relay.