91 s-10.......

Hey, i have a 1991 chevy s-10. It has the digital dash. about every 3 months at random when i start the truck the flashers will be going but the switch isnt on and it doesnt show the flashers are on, on the dash. But when i get out and look they are flashing. it does this for about 20 secounds then stop then starts again it does that 3-4 times. then its fine untill you start the truck again. But it only does this about 20 times then its fine for another 3 months or so...........

Any ideas would be great

Thanks Derek