Turn signal switches house multiple functions in modern vehicles, so their failure can make driving unsafe. However, replacing these components is a straightforward process. If yours misbehaves, here’s how to install a turn signal switch.
What Is a Turn Signal Switch?
A turn signal switch is a lever-operated switch that controls the activation and deactivation of the turn signal lights.
Japanese cars usually have this switch mounted on the right side of the steering wheel.
Therefore, pushing it up turns on the flashing indicator bulbs on the left side of the vehicle.
A turn signal switch mounted on the right side of the steering wheel
Pushing it down turns on the right-side blinker bulbs. The switch also activates the dashboard indicator lights, which flash at the same speed as the exterior ones.
However, most European vehicles have this switch mounted on the left side of the steering wheel.
A turn signal switch mounted on the left side of the steering wheel
In some vehicles, the turn signal switch also houses the headlight, foglight, horn button, or windshield wiper controls, making it a combination or multifunction switch.
How Does a Turn Signal Switch Work?
A turn signal switch contains four components.
- Switch mechanism
- Cancel cam
- Switch operation lever
- Wiring system
If it is a multifunction switch, the headlight, foglight, wiper, and horn button controls have simple manual switching implementations.
However, the turn signal mechanism operates differently.
A combination turn signal switch that includes a horn button
The switch activates the corresponding blinker bulbs when you push the lever up or down.
Older vehicles relied on thermal bimetallic strips to create the on/off contact.
Bimetallic strip curving under hot, room, and cold temperature conditions
But modern vehicles replace this mechanical switching with modules or computers, which use software to blink the lights.
When you activate the turn signal, the light remains on until either of these conditions becomes true: you push the lever back to its center position, or the cancel spring/cam returns it.
After making the turn, the cancel cam follows the steering wheel back to the center position, canceling or returning the turn signal switch.
Signs of a Faulty Turn Signal Switch
Having gone through the turn signal working mechanism, you can tell if you have a faulty switch if you experience these symptoms.
- Dashboard and exterior indicator lights don’t turn on
- Turn signals don’t cancel when turning the steering wheel back to the center position
- Other switches attached to the lever don’t work. For instance, the headlights might fail to turn on when you rotate the switch.
A dashboard right turn signal light
These five problems can cause the turn signal switch failure.
- Wearing Out: All car components wear out over time, meaning failure is inevitable. The turn signal switch wears out as you push the lever up and down. Eventually, you’ll have to replace the component.
- Looseness: The turn signal lever can also become loose over time, or the switch might loosen from its mounting surface. You might have to fix or replace the switch depending on the issue.
- Breaking: Some turn signal switches can break when worn out. A sudden impact can also break these mechanisms, causing failure.
- Corrosion: If you expose the switch to water or other corrosive materials, you will damage the electrical contact surface or stiffen the lever. You can clean the corrosion if it is not severe.
- Damaged Electrical Connector: Turn signal switch connectors can break or become loose over time, increasing the risk of shorting. And if short-circuiting occurs, it will burn the connector, damaging it further. You can replace the connector alone instead of the entire switch.
How To Install a Turn Signal Switch
Some vehicles have the turn signal switch mounted on the steering column, while others have it screwed to the side of the column.
But in all options, the switch is right behind the steering wheel. This position allows you to operate it when your hands are on the wheel.
Turn signal and wiper switches that mount to the steering column
Once you’ve located this lever, follow these steps to replace the switch.
Step 1: Disconnect the Power Source
Loosen and remove the negative terminal from the battery to prevent short-circuiting when replacing or repairing the switch.
Step 2: Remove the Switch
Unscrew and remove the plastic panels that cover the switch to access it.
Use the same screwdriver to undo the screws that hold the switch to the steering column or its side.
Pull out the switch and disconnect the wire harness connector to free it.
Step 3: Inspect the Switch
Check if the switch has physical damage on the plastic surfaces or corrosion on the metallic parts.
Also, check if the lever or knob switches for the headlights and other components feel loose.
If the switch is repairable, you can fix it and save the money you would use to buy a replacement part.
Check if you can tighten the loose parts or clean the corroded contacts using a cotton swab soaked in alcohol.
Also, test the switch for continuity using a multimeter to determine if the contacts are faulty.
If you can repair the switch and the multimeter tests indicate it is okay, return it and skip to step 5. Otherwise, proceed to the next step.
Step 4: Replace the Switch
Place the new and old switches side-by-side to see if they are identical. If they match, connect the harness to the new switch, then fit it on the column.
Secure it using the screws you removed earlier, then fit the plastic panels to cover the mechanism.
A multifunction turn signal lever in a luxurious vehicle
Step 5: Test the Switch
Reconnect the negative battery terminal and test the switch. Turn on the ignition and activate all the controls mounted on it.
If everything looks good, you’re good to go. Otherwise, you’ll have to troubleshoot the issue further.
How Much Does It Cost To Install a Turn Signal Switch?
The cost of the replacement part varies depending on the car’s make and age (generation). It ranges from about $20 to as high as $170 for some premium brands.
If you are a DIY person, you don’t have to worry about labor costs. But if you want a technician to install the switch, be prepared to part with around $50-$100.
Therefore, the total cost will be $270 at most. We recommend following the replacement steps above to lower this cost.
Turn signal switches rarely fail because they operate in a dry environment inside the cabin.
But replacing the unit should take a few minutes if you notice the failure symptoms described above.
Follow the steps above, and you’ll complete the process in no time. But if you need the required wiring harness, contact Cloom Tech.