my 99 gmc jimmy turn signal would blink quite fast as if it was burnt out, but they wernt even working at all, just making noise, i took it to a mechanic and i had a cracked line somewhere and it was allowing water to get into the line and short it out, therfore not allowing the turn signal to work, so in the winter it would work because it froze the water and would no longer short,but as soon as i got warm it quit working
