I have a 2001 Ford Explorer that was doing the samething. The trouble started when the ouside temperature got cold. I replaced the flasher unit and have not had a problem since.
My guess would be the turn signal switch lever itself is defective.
Bad turn signal flasher.
One of you signal lamps is probably burned out. Turn on the signal and walk around the car, bet-ya you find one turn signals isn't lighting up. Some times it is a bad connection at the bulb. The bulb sockets are cheaply made.
You have a turn signal light-bulb out .
Turn signal relay needs to be replaced. If you turn on the hazard (emergency) switch, all the signal lights should come on. This says the lights are okay.
Check/replace turn signal flasher
The Turn Signal Switch is bad in the column and needs to be replaced.
Check bulbs - double filamented with smaller being for brake light and turn signal Bad switch? Bad turn signal flasher?
I would suspect the signal switch is at fault.
Probably the turn signal/hazard flasher went bad. On some vehicles they are separate units, but on some vehicles they are the same unit.
You have a dual-filament signal bulb somewhere with a bad ground. Turn the headlights and turn signal on. The bulb with the bad ground will go completely out at times, even though the headlights are on.
a bulb is out