Wat in the world can be wrong with it?

2000...well it doesn't take long for corrosion to start building up on your battery and connecting lugs, so the first think I'd do is train a garden hose on the corrosion, then undo the clamps and wirebrush them clean and the posts too, look at the other end of the negative cable to assure that the ground is connected solidly to the chassis and to the engine with no corrosion. once you know you've got reliable battery power, should look for a new flasher unit, but probably won't need it because you'll have a renewed grounding and power to connect to...and problem will magically disappear.

Usually the 4ways and the blinkers have separate flashers check the fuse box again for a separate blinkers flasher.

thats correct the hazzard switch is not the 'blinker' switch,the turn stalk left and right controls the blink blink thing,and you need a flasher ,for that circut replaced simpley pluged in at fuse panel,see how easy it is to waste time and money, have fun

the circuit boards and bulb holders for the rear lights have been known to go bad, with a test light at the rear lamp connectors check for voltage with the turn signals on,

if your blinker lights are blinking fast on one side or the other recheck your bulbs.