Japanese and most Asian vehicles have the wiper switch wiring on the left side of the steering wheel, while European cars have them on the right side.
Regardless of the position, the wiper switch wiring operates the same way to complete the circuit to power the wiper motor and washer pump.
If this switch fails or has a wiring malfunction inside, replacing it or repairing the wires is a simple task.
Let’s look at the wiper switch wiring procedure to help you handle this project as a DIY task.
Table of Contents
- How Wiper Switch Wiring Works
- Wiper Switch Wiring
- How To Replace a Wiper Switch
- How To Replace an Intermittent Wiper Relay
- Wrap Up
How Wiper Switch Wiring Works
Wipers don’t use relays, unlike headlights and other high-current draw circuits in vehicles. The wiper motor has a relatively low power rating, making it safe to handle the connection directly on the switch.
However, some vehicles have the relay inside the wiper motor, which makes the wiring simpler. On the downside, replacing a faulty relay in this combined assembly will be costly because you’ll have to buy the complete motor.
A wiper motor
The same case applies to the rear windshield motor. It can either have a direct control switch or a relay.
In a nutshell, the motor’s electrical current rating determines whether its switching mechanism needs a relay. Typical ones use 2-4 amperes in 6V, 12V, or 24V configurations.
But the intermittent wiper switching you adjust using a knob to set the wiping intervals requires a relay.
Since this system has some level of automation, it uses a timer to activate a relay. Once activated, the relay completes the circuit to power the wiper motor.
A wiper mechanism with the motor in the middle
This relay can be external or inside the motor, so you might not know it exists when connecting the wires.
The front windshield motor differs from the rear one because it has three brushes instead of two, giving it two-speed settings. Usually, the slow speed runs at 45 RPM while the high-speed spins at 65 RPM.
The final component of the system is the washer pump, which sends water via jets to the front and rear windshields or front only, depending on the vehicle.
A windshield wiper washer pump
Wiper Switch Wiring
Considering the features of the wiper system described above, this switch circuit must have a hot power wire linking to the fuse in the fuse box and a ground wire to keep the electrons flowing.
There’s also a park switch wire that controls the self-parking feature. Whenever you switch off the wipers, they must rest in the recess under the hood’s edge. This wire ensures they stop at the correct spot by powering the motor until it pushes the wiper blades down.
A set of light and wiper switches
The other conductors are for the high & low-speed connections and a power wire to supply electrical current to the washer pump directly or its solenoid.
If the vehicle has a rear windshield wiper, the wiring layout above also applies to it. Each motor and washer pump has its ground connection to the vehicle’s body.
How To Replace a Wiper Switch
You will need the following tools.
- Allen key set
- Pair of pliers
- Screwdriver
- Clip remover
- Wrench set
- Ratchet
- Seal remover
- Socket set
- Torque wrench
Step 1: Remove the Panel
Undo the plastic pieces around the wiper switch to access the stock switch.
Step 2: Loosen the Switch Bolts
Use the ratchet or socket wrench to unfasten the bolts holding the factory windshield wiper switch to the steering column.
Steering column switches, including the wiper switch
Step 3: Replace the Wiper Switch
If the factory switch is faulty, replace it with a stock or after-market switch. But we recommend the former for seamless fitting and wiring.
The most critical part of this step is to connect the wires. Usually, these switches have six wire colors.
- Red wire connects to the positive battery terminal via a fuse in the fuse box.
- Black wire links to the earth, ground (car body), or the battery’s negative terminal
- The yellow wire connects to the motor’s low-speed green wire
- White wire links to the motor’s red high-speed wire
- The switch’s blue wire attaches to the wiper motor’s blue wire terminal for the park function
- Brown wire powers the washer pump
Step 4: Testing
After making these connections, test the switch before reinstalling it to the steering column. If everything functions as required, proceed to step 5.
Step 5: Reassemble the Switch
Fasten the wiper switch to the steering column, then reassemble the plastic panels. Test the lever again after installation to ensure the final assembly is okay.
A set of disassembled steering column switches, including the wiper switch
How To Replace an Intermittent Wiper Relay
A relay is also a switch. So, let’s look at how to replace this component if it is faulty. You will know this part is non-functional if the high and low-speed settings work, but the intermittent setting does not when you activate it.
This feature is handy if the rain is not strong enough to engage the low-speed wiper setting. Some motors have this relay as an internal component, meaning you must replace the entire unit. But if it is external and in the fuse box, you can fix the issue using these steps.
A wiper switch with intermittent wiping settings
Step 1: Find the Intermittent Relay in the Fuse Box
Some modern vehicles can have multiple fuse boxes, so identify the location of the intermittent relay in these boxes. You can use the vehicle’s wiring diagram to locate this device.
Step 2: Remove the Relay
Switch off the ignition, then undo the fuse box cover. Remove the relay by hand or using a screwdriver if stuck in the slot.
Step 3: Fit in the New Relay
Insert the new relay, then the fuse box cover, and test the system. You must turn on the ignition before trying the intermittent wiper function.
Wrap Up
A wiper switch houses several switching mechanisms, meaning you have several wires to connect to run the system.
So follow the steps above and ensure you get the color coding correct. And check the intermittent relay, as well.
That’s it for this article. Check out this steering-column wiring harness replacement process to help you fix the entire system if it is faulty.
