Circuit Description
The body control module (BCM) controls the illumination dimming of all of the control switch indicators. The BCM sets the control switch indicator illumination level according to the instrument panel (I/P) dimmer switch signal received when the component is activated and the indicator is ON. The BCM also activates the headlamp on indicator.
Voltage for the LED dimming signal, instrument panel lamps dimming control, as well as the backlight lamps control circuits is from the TBC 3 fuse 16 in the underhood fuse block directly through the BCM to these circuits.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B0951 Headlamps On Indicator Circuit
Conditions for Running the DTC
The battery voltage must be between 9.0-16.0 volts.
Conditions for Setting the DTC
| • | The headlamp on indicator control circuit is open, shorted to ground, or shorted to battery positive voltage. |
| • | The LED dimming signal circuit is open, shorted to ground, or shorted to battery positive voltage. |
| • | The backlight lamps control circuit is shorted to ground. |
| • | The instrument panel lamps dimming control circuit is shorted to ground. |
| • | There is a loss of the underhood fuse block TBC 3 battery supply voltage to the BCM for 1 second. |
Diagnostic Aids
| • | Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections. |
| • | A short to ground in the following circuits will cause the TBC 3 fuse to open. |
| - | The backlight lamps control. |
| - | The instrument panel lamps dimming control. |
| - | The LED dimming signal. |
| - | Battery positive voltage from the underhood fuse block TBC 3 fuse. |
| • | An open in the TBC 3 fuse will cause the BCM to set the following DTC: |
| - | B0951 |
| - | B2610 |
| - | B2625 |
Action Taken When the DTC Sets
The headlamps on indicator will remain ON with the headlamps OFF.
The headlamps on indicator will remain OFF with the headlamps ON.
Conditions for Clearing the MIL/DTC
| • | This DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History and current DTCs can be cleared using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Determines if it is the headlamp on indicator circuit or the BCM.
-
Determines if it is the headlamp on indicator circuit or the BCM.
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After replacement of the BCM you must calibrate the new module for proper operation.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||
2 |
Does the headlamp on indicator respond as expected? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||
3 | Is the TBC 3 fuse in the underhood fuse block open? | Go to Step 4 | Go to Step 5 | ||||||
4 | Test the following circuits for a short to ground:
Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | ||||||
5 | Connect a test lamp between the LED dimming signal circuit of the headlamp switch and ground. Does the test lamp illuminate? | Go to Step 6 | Go to Step 7 | ||||||
6 | Test the LED dimming signal circuit of the headlamp switch for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 16 | Go to Step 8 | ||||||
7 | Test the LED dimming signal circuit of the headlamp switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 16 | Go to Step 12 | ||||||
8 | Test for a ground signal on the headlamp ON indicator control circuit at the headlamp switch. Refer to Circuit Testing and Wiring Repairs. Is a signal present? | Go to Step 9 | Go to Step 10 | ||||||
Test the headlamp indicator control circuit of the headlamp switch for a short to ground. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 16 | Go to Step 11 | |||||||
Test the headlamp on indicator control circuit for the following:
Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 16 | Go to Step 12 | |||||||
11 | Inspect for poor connections at the harness connector of the headlamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 16 | Go to Step 14 | ||||||
12 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 16 | Go to Step 15 | ||||||
13 | Repair the battery positive voltage circuit of BCM from the TBC 3 fuse in the underhood fuse block. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 16 | -- | ||||||
14 | Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | Go to Step 16 | -- | ||||||
Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 16 | -- | |||||||
16 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||
