The signal light does not turn off.
The combination lights in the rear are known to take on water, due to defective seals. This could short the light socket, and a light may stay on. I recommend having a mechanic, like one from YourMechanic, inspect your turn signal lights to see if water has been, or is currently in, the lights and is shorting the sockets out.
Have a car question? Get free advice from our top-rated mechanics.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%