Kia Rio: Windshield Wiper/Washer / Rain Sensor

Kia Rio 2017-2024 YB Service Manual / Body Electrical System / Windshield Wiper/Washer / Rain Sensor

Components and components location

Schematic diagrams
Circuit Diagram

Description and operation
Integrated Rain Sensor

Integrated rain sensor (A) controls three systems: front wiper, auto-light, and central air conditioner.


Wiper Control System

When the multifunction switch on the right receives "AUTO" switch signal, the integrated rain sensor detects the amount of rainfall. The sensor is installed inside the upper part of the front window for wiper motor control.

This system automatically controls the operating duration and speed of the wipers depending on the measured amount of rainfall even if the driver does not operate the wiper switch.

Functions and Operating Principles

Basic Principle


Detecting the amount of rainfall

The light (beam) emitted from light emitting diodes (LED) is totally reflected on the external surface of the windshield and comes back to the photo diodes. When there is water on the external surface of the windshield, the light is optically separated and reflected partially and the remaining brightness is measured by the photo diodes. Water remaining on the windshield results in the light being not totally reflected. The loss of brightness due to this indicates how much the glass surface is wet.


Rain sensor might malfunction due to the interferences listed below.


Dust on the measuring surface and other surfaces on the light path (surface of light emitting diodes and photo diodes, fiber optics, bracket, and glass surface of windshield joint area) weakens the received light.


Movement of windshield and bracket


Movement of bracket due to vibration


Damaged wiper blade


When the integrated rain sensor does not operate or malfunctions, the driver should operate the wiper switch manually.

Automatic Operation


Operational status of rain sensor

Operation Mode
Direct Mode
This is the basic operating status when the rain sensor detected dry windshield with wiper switch in"Auto". In this mode, the integrated rain sensor determines the operating mode of wipers depending on the rainfall and its duration.
Intermittent Mode
Integrated rain sensor activates the intermittent mode when wiper operation is done successively more than twice with a pause of 0.5 - 5 seconds.
Low Speed
The wiper operates continuously in low speed
High Speed
The wiper operates continuously in high speed

Safety Function


When there is ice or foreign matter in the detecting area, integrated rain sensor cannot recognize the condition for operation correctly.

Detecting Special Conditions


Rain sensor

Special Condition
Operation based on special conditions detecting
When integrated rain sensor detects a high level of water (splash) in Direct or Intermittent mode, the system switches from Park to High speed. Then, wiping is done once in High speed and once more in Low speed. If the condition of rainfall does not change after wiping, it returns to the original condition (Direct or Intermittent).
Smearing is a thin oil film that has dried fast and occurs when a small amount of rainfall is wiped by a dirty or worn-out wiper blade. Operational signal should not be issued when smearing occurs in Direct or Intermittent mode.
When no change is detected after wiping, integrated rain sensor determines that the windshield is dirty. In this state, operational signal should not be issued. If the windshield becomes clean (for example, by washer fluid), the integrated rain sensor returns to the normal condition.
Washer fluid
Integrated rain sensor does not respond to the washer fluid during the Washer mode. In other words, wiping speed does not change even if the washer fluid is sprayed (automatic operation of the washer pump is not reflected in the functioning of integrated rain sensor).

Repair procedures

Do not damage or touch the silicone (coupling medium).

Be careful so that the silicon is not contaminated by foreign substances, dust, etc. .

Use caution, as the silicon may be damaged if you try to separate the rain sensor forcibly.


The dust or foreign substance on the rain sensor may have bad influence on the performanec of the rain sensor. In order to ensure accurate function of the rain sensor, protect the sensor surface with the protection cover until the sensor is installed on the bracket.

The coupling pad on the rain sensor surface is adhesive and the coupling pad may stick to the windshield during the use depending on the environment condition.

Therefore, it may be damaged when you try to remove the rain sensor from the windshield forcibly. Use caution when sepearting it from the windshield.


Reomve the mirror wiring cover (A).


Disconnect the rain sensor connector (A).


Be careful not to damage the cover latch by applying excessive force. To remove the latch, pull aside the latch using the cover hole with a small flat-blade screwdriver (A).


Insert a small flat-blade screwdriver (-) into a space at the bottom or top, between the rain sensor and bracket. .


Pull the rain sensor slowly up and down in the vertical direction of the glass, then disassemble the rain sensor slowly from windshield without damaging the silicone on the sensor.


It may be damaged when you try to remove the rain sensor from the windshield forcibly. Use caution when sepearting it from the windshield.

When detaching the silicone under a high temperature, it may be easily damaged because of the adhesive strength of the silicone. Remove the silicone in a cool enviroment.


Rain sensor module is attached to the front windshield by glue. To replace the front windshield, remove the rain sensor module from the existing front windshield and install on the new front windshield.


Check the operation of the rain sensor and the light sensor before mounting.

Check the sensor for silicon damage.

Check whether the rain sensor connector is tightened.

Check whether the rain sensor and bracket are properly tightened.

Check whether the sensor mounted area is free from foreign matters.

Recalibrate sensitivity of the swtich if the auto-wiping operation is insensitivity or too much sensitive.

In case the silicone of the rain sensor is normal or slightly damaged as shown in the below images, it can be reused.

Damage within 1.5 mm of outer part

In case the silicone of the rain sensor is damaged as shown in the below images, it should be replaced with a new silicone.

Foreign substances


In case the silicone of the rain sensor is damaged it should be replaced it as shown below.

1) Remove the damaged silicone gel pad from the lens plate completely.


Be careful not to damage or contaminate the surface of the lens plate during removal.

2) Attach the new silicone gel pad aftet removing the silicone paper (A) then remove the transperent film (B).


When attaching the silicone gel pad to the sensor, be careful not to contaminate

It is very important that the silicon (coupling pad) is completely pushed against the windshield and stuck without any air bubble.

In case of replacing the damaged windshield, you may reuse the undamaged exisitng rain sensor.

The windshield glass has to be clean and free of contamination or foreign substances.


Connect the rain sensor connector.


Push one of the latch of spring arm (A) down until it snaps and you hear a click sound.

And then push the latch of second spring arm (B) for keeping the sensor in right position.


Do not snap both spring arms at the same time.

An incorrectly mounted snap connection may cause malfunctions of the rain/light sensor.

Gel pad

Remove the damaged silicone gel pad completely on the lens plate of rain sensor.


The silicone gel must be fully detached from the rain sensor by rubbing it off with the fingers without any tool.

The surface of the lens plate must neither be damaged nor polluted by this activity.


It is recommended to remove any residues from the lens plate surface with pressurized air.


Remove the two protection foils (A) from the gel pad.


Attach the silicone gel pad (A) on the lens plate of rain sensor by hand.


In case that silicone gel pad of rain sensor is polluted by foreign substances, remove the foreign substances by using the sticker roller.

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