Diagnostic Instructions
| • | 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 the diagnostic category. |
DTC Descriptors
DTC B1395 03 : Voltage Below ThresholdDTC B1395 07 : Voltage Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Body Control Module (BCM) 1 Fuse B+ Supply | B1395 03 | B1395 03 | -- | -- |
Body Control Module (BCM) 7 Fuse B+ Supply | B2652 00 | B2652 00 | -- | -- |
I/P Dimmer Switch Signal | B1395 03 | 1 | 1 | -- |
I/P Lamps Dimmer Switch Signal | B2652 00 | 1 | 1 | -- |
I/P Dimming Voltage Reference | B1395 03 | B2652 00 | B1395 07 | -- |
Indicator Dimming Control | B2625 00 | 1 | 1 | -- |
LED Backlight Dimming Control | B2610 00 | 1 | 1 | -- |
I/P Dimmer Switch Low Reference | -- | 1 | -- | -- |
I/P Dimmer Switch Ground | -- | 1 | -- | -- |
1. Interior Backlighting Malfunction | ||||
Circuit/System Description
The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the light are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level. For more detailed information concerning interior lamp operation refer to Interior Lighting Systems Description and Operation .
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
B1395 03
DTC B1395 03 will set for the following conditions:
| • | The BCM detects a short to ground in the I/P dimming voltage reference circuit. |
| • | The BCM detects a short to ground in the I/P dimmer switch signal circuit. |
| • | The BCM detects a short to ground or an open/high resistance in the BCM 1 fuse B+ circuit. |
B1395 07
The DTC will set when the BCM detects a short to voltage in the I/P dimming voltage reference circuit or the vehicles system voltage exceeds the normal operating range of 16 volts.
Actions Taken When the DTC Sets
| • | The I/P dimmer switch will not operate. |
| • | The I/P dimming lamps will not illuminate. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Interior Lights Dimming Schematics
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, observe the scan tool Dimming Control Reference voltage. The reading should display battery voltage.
| ⇒ | If less than the specified range, refer to I/P Dimming Control Malfunction. |
| ⇒ | If within the specified range, refer to I/P Dimmer Switch Malfunction. |
Circuit/System Testing
I/P Dimmer Switch Malfunction
- Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
- Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 10.
- Ignition ON, test for B+ between the I/P dimming voltage reference circuit terminal 5 and ground.
- Install a 3A fused jumper wire between the signal circuit terminal 9 and the B+ voltage reference circuit terminal 5. Verify the scan tool dimming control signal parameter is greater than 2.5 volts.
- If all circuits test normal, test or replace the I/P dimmer switch.
| ⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
| ⇒ | If less than the specified range, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
I/P Dimming Control Malfunction
- Ignition OFF, disconnect the C3 harness connector at the BCM.
- Ignition ON, verify that a test lamp illuminates between the BCM 1 fuse voltage supply circuit terminal 3 and ground.
- If all circuit tests normal, replace the BCM.
| ⇒ | If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
