Front Fog Lamps Malfunction
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Headlight Switch 12V Reference
|
1
|
1
|
1
|
-
|
Headlight Switch Signal
|
1
|
1
|
2
|
-
|
Front Fog Lamp Control
|
B2530 02
|
B2530 04
|
B2520 01
|
-
|
Right Front Fog Lamp Ground
|
-
|
3
|
-
|
-
|
Left Front Fog Lamp Ground
|
-
|
4
|
-
|
-
|
1. Front fog lamps inoperative
2. Front fog lamps always ON
3. Right front fog lamp inoperative
4. Left front fog lamp inoperative
|
|
|
Circuit/System Description
The front fog lamp relay is supplied with battery voltage at all
times. The front fog lamp switch signal circuit is grounded
momentarily by pressing the front fog lamp switch. The body control
module (BCM) energizes the front fog lamp relay by applying ground
to the front fog lamp relay control circuit. When the front fog
lamp relay is energized, the relay switch contacts close and
battery voltage is applied through the front fog lamp fuse to the
front fog lamp supply voltage circuit which illuminates the front
fog lamps. With the front fog lamp switch activated the BCM sends a
message via serial data to the instrument cluster requesting the
instrument cluster to illuminate the front 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 Front
Fog Lamps test. The front fog lamps should be ON/OFF. |
• |
Ignition ON, perform the
instrument cluster All Indicators test ON and OFF test. The front
fog indicator should be ON/OFF. |
Circuit/System Testing
Front Fog Lamp Malfunction
1. |
Ignition OFF, disconnect the
appropriate harness connector at the front fog lamps listed
below: |
|
• |
E29LF Fog Lamp - Left
Front |
|
• |
E29RF Fog Lamp - Right
Front |
2. |
Disconnect the negative
terminal of the C1 Battery. |
3. |
Test for less than 5 Ω
between the appropriate front fog lamp ground circuit harness
connector terminal 2 and ground. |
⇒ |
If greater than the specified value, test the
ground circuit for an open/high resistance. |
4. |
Reconnect the negative
terminal to the C1 Battery. |
5. |
Remove the F26UA fuse. Verify
that the front fog lamps does not illuminates. |
⇒ |
If any front fog lamp does illuminate, test the
signal circuit for a short to voltage. |
6. |
Install a 10 A fused jumper
wire between the fuse output contact and B+. Verify that the front
fog lamps illuminate. |
⇒ |
If the front fog lamps does not illuminate, test
the signal circuit terminal for a short to ground or an open/high
resistance. If the circuit tests normal, replace the appropriate
front fog lamp. |
7. |
Disconnect the X2 harness
connector at the X50A Fuse Block - Underhood. |
8. |
Connect a test lamp between
the signal circuit terminal 46 X2 and B+. |
9. |
Ignition ON, perform the Front
Fog Lamps test. The test lamp should turn ON and OFF when changing
between the commanded states. |
⇒ |
If he test lamp is always ON, test the signal
circuit for a short to ground. If the circuit tests normal, replace
the K9 Body Control Module. |
⇒ |
If he test lamp is always OFF, test the signal
circuit for a short to voltage or an open/high resistance. If the
circuit tests normal, replace the K9 Body Control Module. |
10. |
If all circuit test normal,
replace the X50A Fuse Block - Underhood. |
Front Fog Lamp Switch Malfunction
1. |
Ignition OFF, disconnect the
X1 and X3 at the K9 Body Control Module. |
2. |
Ignition ON, 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 a short to voltage. |
3. |
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 a short to voltage. |
4. |
Ignition OFF, test for
infinite resistance between the 12 V reference circuit terminal 4
X3 and ground. |
⇒ |
If less than the specified value, test the 12 V
reference circuit for a short to ground. |
5. |
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 a short to voltage. |
6. |
Test for infinite resistance
between the signal circuit terminal 9 X1 and ground. |
⇒ |
If less than the specified value, test the signal
circuit for a short to ground. |
7. |
Press and hold the front fog
lamp switch button. |
8. |
Test for 2.7-3.1 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. |
Front Fog Indicator Malfunction
Ignition ON, command the instrument cluster All Indicators test ON
and OFF with the scan tool. The front fog indicator lamp should be
ON/OFF when changing between the commanded states.
If the front fog indicator stays always on or always off, replace
the P16 Instrument Cluster. If the front fog indicator is changing
between ON and OFF, replace the K9 Body Control Module.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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