Weird turn signals

My 92 Dakota is back to the "I only work in the morning" attitude. The turn signals work fast the first time I start the truck each day but dont work after that. What I mean by fast is they turn on and off quicker than I think is normal. Sounds strange but is consistant. Any sujestions as to where to look???

Dad's 99 Intrepid does that. The left turn signal flashes very fast. It turned out to be a bad connection in the tail light socket. It was cleaned out and worked fine for 3 or 4 months...now it's doing it again.

Thanks, I guess I should start at the sockets and make sure they are clean and have good contact.