• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Rain Sensor B+ | 1 | 1 | -- | -- |
Rain Sensor Ground | -- | 1 | 1 | -- |
Rain Sensor Signal | B370A 39 | B370A 39 | B370A 39 | B370A 39 |
1. Windshield Outside Moisture Sensor Malfunction |
B+ voltage is supplied to the windshield outside moisture sensor. Whenever the ignition is ON, or in accessory positions, the body control module (BCM), sends the turn signal / multifunction switch status by using a pulse width modulated (PWM) signal. When a wipe cycle is needed, the windshield outside moisture sensor sends a PWM voltage signal to the BCM, initiating the wiper operation. The BCM commands the windshield wiper motor wipe cycles. If a fault occurs at any time between the windshield outside moisture sensor and BCM, the BCM will use the inputs from the turn signal / multifunction switch in the delay positions to operate the windshield wiper motor at continuous variable delay intervals.
• | Ignition ON. |
• | The system voltage is between 9 V and 16 V. |
The BCM receives an invalid signal from the windshield outside moisture sensor.
• | If the BCM loses communication with the windshield outside moisture sensor while the windshield outside moisture sensor was requesting single wipes, it shall fail soft the wipers operation to front wiper manual - intermittent with a fixed dwell time of 4 seconds. |
• | If the BCM loses communication with the windshield outside moisture sensor while the windshield outside moisture sensor was continuously requesting low, it shall fail soft the wipers operation to front wiper manual - low. |
• | If the BCM loses communication with the windshield outside moisture sensor while the windshield outside moisture sensor was continuously requesting high, it shall fail soft the wipers operation to front wiper manual - high. |
A current DTC clears when the diagnostic runs and passes.
Wiper/Washer System Description and Operation
Control Module References for diagnostic tester information
Ignition ON, S78 Turn Signal/Multifunction Switch in the low position. The windshield wipers should operate at low speed.
⇒ | If the windshield wipers do not operate, refer to Windshield Wiper System Malfunction. |
⇒ | If greater than the specified value, test the ground circuit for an open / high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ voltage circuit for a short to ground or an open/high resistance. |
⇒ | If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM). |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | LINK |
• | Control Module References for BCM replacement, setup, and programming |