Rear Fog Lamps Malfunction
Diagnostic Instructions
Diagnostic Fault Information
Circuit
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Short to Ground
|
Open/High Resistance
|
Short to Voltage
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Signal Performance
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Headlight Switch 12V Reference
|
1
|
1
|
1
|
-
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Headlight Switch Signal
|
1
|
1
|
2
|
-
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Rear Fog Lamps Control
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B2540 02
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B2540 04
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B2540 04
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-
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1. Rear Fog Lamps Inoperative
2. Rear Fog Lamps Always ON
|
|
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Circuit/System Description
The rear fog lamp switch signal circuit is grounded momentarily
by pressing the rear fog lamp switch. The body control module (BCM)
energizes the rear fog lamp supply voltage circuit which
illuminates the rear fog lamp. With the rear fog lamp switch
activated the BCM sends a message via serial data to the instrument
cluster requesting the instrument cluster to illuminate the rear
fog indicator.
Reference Information
Schematic Reference
Fog Lights 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, perform the scan
tool Rear Fog Lamps Switch parameter. The reading should change
between Active/Inactive when changing between pressed and released
rear fog lamp switch button. |
⇒ |
If not change between Active and Inactive, refer
to Rear Fog Lamp Switch Malfunction. |
• |
Ignition ON, perform the
instrument cluster All Indicators test ON and OFF test. The rear
fog indicator should be ON/OFF. |
⇒ |
If not change between ON and OFF, refer to Rear
Fog Indicator Malfunction. |
• |
Ignition ON, perform the Rear
Fog Lamp(s) Relay test. The rear fog lamp should be ON/OFF when
changing between the commanded states. |
⇒ |
If not change between ON and OFF, refer to Rear
Fog Lamp Malfunction. |
Circuit/System Testing
Rear Fog Lamp Switch Malfunction
1. |
Ignition OFF, disconnect the
X1 and X3 harness connector at the K9 Body Control Module.
|
2. |
Test for less than 0.3 V
between the 12 V reference circuit terminal 4 X3 and ground.
|
⇒ |
If greater than the specified value, test the 12 V
Reference circuit for an short to voltage. |
3. |
Test for infinite resistance
between the 12 V reference circuit terminal 4 X3 and ground.
|
⇒ |
Test for infinite resistance between the 12 V
reference circuit terminal 4 X3 and ground. |
4. |
Test for less than 0.3 V
between the signal circuit terminal 9 X1 and ground. |
⇒ |
If greater than the specified value, test the
signal circuit for an short to voltage. |
5. |
Test for infinite resistance
between the signal circuit terminal 9 X1 and ground. |
⇒ |
If less than the specified value, test the signal
circuit for an short to ground. |
6. |
Press and hold the rear fog
lamp switch button. |
7. |
Test for 2.0-2.4 kΩ
between the signal circuit terminal 9 X1 and the 12 V reference
circuit terminal 4 X3. |
⇒ |
If not within the specified range, test the 12 V
reference circuit and the signal circuit for an open/high
resistance. If the circuit test normal replace the S30 Headlamp
Switch. |
8. |
If all circuit test normal,
replace the K9 Body Control Module. |
Rear Fog Indicator Malfunction
2. |
Command the instrument cluster
All Indicators test ON and OFF with the scan tool. The rear fog
indicator lamp should be ON/OFF when changing between the commanded
states. |
⇒ |
If the rear fog indicator stays always on or
always off, replace the P16 Instrument Cluster. |
⇒ |
If the rear fog indicator is changing between ON
and OFF, replace the K9 Body Control Module. |
Rear Fog Lamp Malfunction
1. |
Ignition OFF, disconnect the
appropriate harness connector at the appropriate tail lamp listed
below: |
|
• |
E43L Liftgate Tail Lamp
Assembly - Left |
|
• |
E43R Liftgate Tail Lamp
Assembly - Right |
2. |
Test for less than 5 Ω
between the appropriate ground circuit harness connector terminal
listed below and ground: |
|
• |
E43L Liftgate Tail Lamp
Assembly - Left harness connector terminal 3 |
|
• |
E43R Liftgate Tail Lamp
Assembly - Right harness connector terminal 2 |
⇒ |
If greater than the specified value, test the appropriate
ground circuit for an open/high resistance. |
3. |
Connect a test lamp between
the appropriate control circuit harness connector terminal listed
below and ground: |
|
• |
E43L Liftgate Tail Lamp
Assembly - Left harness connector terminal 4 |
|
• |
E43R Liftgate Tail Lamp
Assembly - Right harness connector terminal 1 |
4. |
Ignition ON, perform the Rear
Fog Lamps Relay Command test. The rear fog lamp should be ON/OFF
when changing between the commanded states. |
⇒ |
If the test lamp is always ON, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K9 Body Control Module. |
⇒ |
If the test lamp is always OFF, test the control
circuit for a short to ground or an open/high resistance. If the
circuits test normal, replace the K9 Body Control Module. |
5. |
If all circuits test normal,
test or replace the appropriate tail lamp. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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