Turn Signal Repair

Easy step by step guide on how to repair an automotive turn signal system that is not working, this information is presented in the order of probability and pertains to most vehicles.

Difficulty Level - 4

Begin with the vehicle on level ground, in park with the engine "OFF".

Step 1 - Turn the ignition key to the "ON" position, (do not start the engine) this will power up the electrical system for testing.

Ignition Switch "ON"

Step 2 - Locate the power distribution center (PDC) or fuse panel to check all system fuses. Learn more - To locate the fuse consult the owner's manual or search Google Images.

Blown Fuse

Step 3 - When a turn signal flasher or relay fails the blinkers will not operate or come "ON", but not blink. A direction signal system is designed to operate with a flasher or blinker unit which interrupts the signal which created the blinking action. Learn more - Locate turn signal flasher in Google Images.

Turn Signal Flasher

Step 4 - When a turn signal switch fails the system will short or go "open" causing the blinker not to operate. Use a test light to test input and output power circuits using a wiring schematic. Learn more - Find a wiring diagram in Google Images.

Turn Signal Lever

Step 5 - A lighting module is sometimes used to control the all vehicle lighting systems, when this module has a problem various lights will fail to operate and the module needs to be updated or replaced (reprogrammed).

Lighting Module

Helpful Information

A turn signal switch is used to operate the direction signal system in a vehicle, which helps communicate an intended direction. Some lighting system designs integrate the turn signal and brake light systems which share the same circuit. Most lighting systems are grounded near the light bulb, which will produce a single bulb operation failure.


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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