More information is required to properly answer your question. Are you referring to the turn signal bulb, flasher or switch?
SWITCH
Need to know what year it is, it makes a difference.
turn signal arm
how can i change the turn singal on a 1990 Chevy lumina
turn signal & wiper relay for a 1998 Chevy blazer
I believe it is in your glove compartment there is an access to your flasher.
multi switch on steering coloum is wearing out
Check the turn signal relay. The four way flasher and the turn signals each have their own relay. It has a fuse for the turn signal
under the battery tray...look up from underneith
how to change front left turn signal bulb on a 2004 chevy express
pivture to change right turn signal
If the turn signal bulbs light but will not flash, the flasher relay is defective, replace it.
Remove the wiring harness from the back of your 1991 Chevy Corsica turn signal. Remove the turn signal retaining bolts. The entire turn signal will come out. Reverse the process to install the new turn signal.