Rain Sensor Circuit: Procedure

1. Check the symptoms of the wiper. Check if the symptoms can be corrected with the information below.
   IT IS RAINING BUT WIPER DOES NOT OPERATE:
   
   

   Condition	Note
   Windshield wiper switch in position other than AUTO	Wiper only operates at AUTO setting
   Rain sensor temperature is -10°C (14°F) or less, or 70°C (158°F) or more	To prevent improper operation, wiper does not operate when rain sensor temperature is -10°C (14°F) or less To prevent damage to rain sensor, it does not operate when outside temperature is 70°C (158°F) or more, or when sensor's interior temperature is 90°C (194°F) or more
   It is drizzling, or there is scattered rain	If rain droplets do not contact rain sensor, or rain droplets are very small, they are not detected

   IT IS NOT RAINING BUT WIPER OPERATES:
   
   

   Condition	Note
   Condensation on windshield	Wiper may operate if condensation occurs in rain sensor detection area. If condensation recurs after rain sensor detection area is wiped, wiper operation may continue.
   Sun rays are strong	If sudden changes in light intensity occur, wiper may operate
   Sudden temperature changes	If sudden changes in temperature occur (A/C heater is used in winter, etc.), wiper may operate
   Object is contacting rain sensor	If inner mirror contacts or strikes rain sensor, wiper may operate

   WIPER OPERATION IS IRREGULAR:
   
   

   Condition	Note
   Wiper blade is deteriorated Windshield surface is oily	Rain sensor detects rain amount when wipers are operating. When rain is not completely wiped off by wipers, decrease in ability to detect amount of rain occurs.
   During scattered rain Heavy rain with large droplets	During scattered rain or when rain droplets are large, rain droplets contact the sensor intermittently, causing wiper operation to be irregular During heavy rain, it is difficult for sensor to learn "no rain" condition, causing wiper operation to be irregular
   Wiper volume is set to minimum	Minimum wiper volume setting is designed to be non-sensitive (for users who prefer non-sensitive operation), resulting in irregular wiper operation
   Problem with wiper motor position signal	When wiper motor position signal has chattering, wiper may operate excessively. During auto wiper operation inspection, if wiper operates several times, and furthermore replacement of rain sensor does not correct problem, wiper motor may be malfunctioning.

OK → END 

NG: Go to next step 

1. Set the windshield wiper switch to the LO and HI setting, and check that the wipers operate normally.

   OK

   Wipers operate normally.

NG → PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

OK: Go to next step 

1. Set the windshield wiper switch to AUTO, and check the problem symptom.

   Problem Symptom	Proceed to
   It is raining but wiper does not operate	A
   It is not raining but wiper operates	B

B → See step   9 

A: Go to next step 

Check the vehicle.

B → See step   10 

A: Go to next step 

1. Activate the washer and check the wiper's ability to wipe.

   OK

   No residue after wipe

NG → See step   13 

OK: Go to next step 

1. Check that the rain sensor is installed properly.

   OK

   When viewed from outside vehicle, rain sensor's tape is not peeling, and has no air bubbles or dust

NG → See step   14 

OK: Go to next step 

1. Check the Data List for proper functioning of the rain sensor.
   RAIN SENSOR:
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Sensor Low Temp Info	Rain sensor cold/NG or OK	NG: Front wiper switch in AUTO position OK: Wiper switch not in AUTO position	-
   Sensor High Temp Info	Rain sensor cold/NG or OK	NG: Front wiper switch in AUTO position OK: Wiper switch not in AUTO position	-

   OK

   Rain sensor operates

NG → See step   11 

OK: Go to next step 

1. Set the windshield wiper switch to AUTO. Wet a swab and squeeze the tip so that it is 4 to 6 mm wide. Touch the swab to the rain sensor detection area and check that the wiper LO operation occurs once.

   Malfunction Operation	Proceed to
   Wiper operates 3 times or more	A
   Any other operation	B

B → See step   11 

A → See step   12 

1. Check that the rain sensor is installed properly.

   OK

   When viewed from outside vehicle, rain sensor's tape is not peeling, and has no air bubbles or dust

NG → See step   14 

OK → See step   11 

1. Check that the rain sensor is installed properly.

   OK

   When viewed from outside vehicle, rain sensor's tape is not peeling, and has no air bubbles or dust

NG → See step   14 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR