Multifunction Switch: What It Is, How It Works, When to Replace, and More

A multifunction switch is actually a cluster of switches built into a single assembly. It typically includes the wiper/washer switch, headlight dimmer, and the turn signals. Some multifunction switches will have levers on both sides of the steering column and require the removal of the steering wheel and airbag clockspring when it is being replaced.

What Does the Multifunction Switch Do?

The multifunction switch makes it easier for you to operate different systems without taking your hands off the steering wheel. Some of its functions include:

• Activates the left or right turn signals and the hazard flashers
• Switches between high and low-beam headlights and/or turns the headlights on or off
• Controls the speed and operation of the windshield wipers
• Activates the windshield washer
• Turns the fog lights on or off
• Controls the horn in some vehicles

How Does a Multifunction Switch Work?

The multifunction switch has multiple switches integrated into its design.. The three main ones are the switching mechanism, lever, and wiring system. The wiper switch will have interval positions that use a stepped resistor array.

On older vehicles, the switch is usually hard-wired to the lights and is designed to handle the load. Newer vehicles usually have reference voltage feeds from modules and resistors in the switch to signal the module what to do.

Also, on older vehicles where the stop lamps and turn signals share the same bulbs, the stop lamp feed will be wired through the switch so that it can divert the stop lamp feed on one side through the flasher when the turn signal is engaged.

Symptoms of a Faulty Multifunction Switch

Some symptoms of a faulty multifunction switch include turn signal issues, headlight problems, and a malfunctioning windshield wiper.

Turn Signal Issues

Because the multifunction switch controls the turn signals, issues with the signals could indicate a faulty switch. These could manifest in different forms, such as a turn signal that’s not working, working intermittently, or not canceling.

If the turn signals are working intermittently, it might be a sign that the multifunction switch is starting to fail. This could be due to wear, but it could also be issues within the electrical system, so it’s best to have the wiring inspected to locate the cause.

Lastly, the multifunction switch has a component called the canceling cam that cancels the turn signals after you make a turn. The cam could be faulty if the switch doesn’t automatically flip back to its neutral position when the steering wheel is returned to center after a turn.

Headlight Problems

Headlight issues could stem from blow-out bulbs but they can also be multifunction switch-related. If you’re having trouble switching between high and low beams, consider inspecting the switch, as it could mean it’s not sending signals to the car computer.

Windshield Wiper Malfunctions

Similarly, issues with the windshield wiper could be due to multifunction switch issues. Like with the headlights, problems within the switch’s wirings could prevent it from effectively sending signals to the computer to turn the windshield on.

How to Test a Multifunction Switch

To begin with, most newer multifunction switches are extremely complex and difficult to test, so be aware of this before you even begin to try and follow the steps below.

It’s actually easier to measure voltage (if you have a schematic and know what to look for) by backprobing the pins at the switch than it is to test the switch.

Having said that, here are some general steps to follow to test a multifunction switch:

• Step 1: Locate the multifunction switch.
• Step 2: Use a screwdriver to remove the screws holding the steering wheel covers in place. Take the cover off to expose the switch.
• Step 3: Disconnect the switch by removing it from the electrical connectors. You might need to remove additional screws or clips holding it in place.
• Step 4: Pull out the old switch from its position.
• Step 5: Use a multimeter to test the switch terminals for continuity.
• Step 6: Set your multimeter to the continuity setting and touch one probe to each terminal.
• Step 7: If you hear a beep, the switch still works, and the issues could lie elsewhere. If there’s no continuity, then the switch needs replacement.

Some models require you to remove the airbags and the steering wheel to access the multifunction switch. While it’s doable on your own, having professional assistance is better in this scenario because it requires numerous steps and proper precautions.

How to Replace a Multifunction Switch

The issues above can be fixed by replacing the multifunction switch, assuming it’s the one responsible for them in the first place. The process varies, depending on the make and model of your vehicle. However, here are some general steps you can follow:

• Step 1: Disconnect the negative battery terminal to ensure safety since the switch is electrically controlled. The terminal is usually a black cable labeled “negative” or a minus sign.
• Step 2: Remove the switch from its position similar to how you removed it to test it out.
• Step 3: Place the new switch in the same position as the old one and reconnect the electrical connectors and secure the switch with screws or clips.
• Step 4: Reassemble the steering column by placing the covers back in place and securing them with screws.
• Step 5: Reconnect the negative battery terminal.

If you’re not confident in replacing the multifunction switch, it’s best to have a licensed mechanic do it. They’re more experienced with vehicle issues and will have the appropriate tools and know-how to properly diagnose and replace the switch.

How Much for a Multifunction Switch Repair?

The average cost of replacing a multifunction switch is around $100. Labor fees are estimated to be between $80 and $105. This doesn’t include taxes, fees, and related repairs, so the price could be higher.