A left rear turn indicator failure notice typically indicates a problem with the left side of the vehicle’s turn signals. This message may be triggered by a malfunctioning bulb, a loose connection, a blown fuse, or a bad wiring harness. In this instance, the mechanic replaced all four bulbs on both the left and right sides of the vehicle, yet the message continues to appear.
When the mechanic asked if the indicator light was blinking or flashing, or if it was solid, the response was that it began normally, but stopped after a few seconds. This could indicate that the left turn signal itself is defective, most likely due to a damaged connection or electrical harness.
The excellent operation of the right turn signal suggests that the problem may be isolated to the left side of the vehicle. It may also indicate a problem with the wiring between the two turn signals or the fuse box. In any event, the issue should be investigated further to confirm that the left rear turn signal is operational.