Replace the signal flasher relay assuming you have physically seen front and rear, left and right signal bulbs flash.
it is your bulb board. The thing your bulbs go into. Had the same problem. 10.00 bucks
the blinker relay is probably bad
your problem could be in the switch its self. unfortunetly they are expensive to replace, i had to actually wire a switch direct to the blinker system.
Check the ground, without a proper ground it will not light up
Check the fuses first.
How about a malfunctioning brake light switch
If the brake lights are not coming on in your car and you have changed the bulbs and the fuses with no results, you could also check the wiring in your '98 Chevrolet Lumina. The wires may be damaged or even broken.
Your Headlight relay may be dead.
Does it have trailer light wiring also? check that too.
Answerif the problem you are having is the high beams work and the low beams don't and you replaced the bulbs already then you should remove and inspect the whole blinker housing arm, mine melted on the inside and i got the new arm right from the dealer for about $85. hope it helpedAlso check the fuses - some model year Windstars have separate fuses for high and low beams.
light bulbs
check your bulbs and fuses check your bulbs and fuses