check the multifunction (turn signal) switch
check and make sure all the lights are on like if a turn signal is out in the front then the signal will stay on in the back when you turn the turn signal on.
Bad turn signal flasher.
my car turn sigal wanted stay under i turn them on my car is a saturn 2001 ls
because you didn't make the turn yet?
change the flasher relay
there are 2 small tabs on the turn signal swith in side the steering colum. these turn the signal off when wheel is straightened after turning. if one or both are broken, signal will not turn off automatically
a bulb is out
The turn signal switch has a cancel tab molded on it, when this tab is broken off the switch stops canceling the signal. To repair it it will require the turn signal switch be replaced.
One of your turn signal bulbs is burned out. Either the front or the back.
usually means you have a bad bulb in turn signal side that is not lit remove lense and replace turn bulb remember the side that is not lit.
turn signal flasher
I've seen some turn signal dash indicators that stay on without flashing just when a bulb is burnt out. If the signal itself is flashing, and especially if the turn signal arm doesn't automatically retract when you turn, there may be a broken spring in the canceling cam inside the steering column.