Automatic Light Malfunction
Diagnostic Instructions
Circuit/System Description
The rain sensor is used to monitor outside lighting conditions.
The rain sensor contains the light sensor. The light sensor
provides raw ambient light/tunnel data and Lights On/OFF
information to the body control module (BCM) via LIN (Local
Interconnect Network) messaging. The BCM monitors the light sensor
signal to determine if outside lighting conditions are correct for
either daytime running lights or automatic lamp control when the
headlamp switch is in the AUTO position. In daylight conditions the
BCM will command the daytime running lights ON. During low light
conditions the BCM will command the low beam headlamps ON.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool Ambient Light Status
parameter. The reading should change between Day and Night when
varying the ambient light.
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
harness connector at the B117 Rain Sensor. |
| 2. |
Disconnect the negative
terminal of the C1 Battery. |
| 3. |
Test for less than 5 Ω
between the ground circuit terminal 2 and ground. |
| ⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
| 4. |
Reconnect the negative
terminal to the C1 Battery. |
| 5. |
Ignition ON, verify that a
test lamp illuminate between B+ voltage circuit terminal 1 and
ground. |
| ⇒ |
If the test lamp does not illuminate, test the B+
voltage circuit for a short to ground or an open/high
resistance. |
| 6. |
Ignition ON, test for 4-12V
between the signal circuit terminal 3 and ground. |
| ⇒ |
If not the specified range, test the signal
circuit for an open/high resistance and a short to voltage . If the
circuit tests normal, replace the K9 Body Control Module. |
| 7. |
If all circuits test normal,
replace the B117 Rain Sensor. |
Component Testing
Dynamic Test
Ignition ON, observe the scan tool Ambient Light Status parameter.
The reading should change between Day and Night when varying the
ambient light.
If not within the specified range, replace the B117 Rain Sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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