2000 car has Left turn signal blinking slowly, the right one is OK. Any help would be greatly appreciated? Thanks

 

Any time one side blinks slower, it means there is not enough current flowing on that side. That can be caused by several things, burnt out bulbs (most common, check them all), bad socket connections, defective turn signal switch, DRL module. First make sure all the lamps are coming on that should light. Compare with the good side. There are two turn lamps for each side on the back, make sure both are coming on. Look for lamps that appear dimmer than the same one on the other side.
Don't be fooled by replacing the flasher and then seeing that it apparently works, Many newer flashers are not affected by the loss of current and will mask the problem.