The BCM directly sends a 5 volt reference voltage to the IP dimmer switch which is then adjusted based on the IP dimmer switch position and returned as a low reference and a signal to the BCM. The BCM uses this signal to directly control the desired level of instrument panel illumination lamp intensity.
The battery voltage must be between 9.0-16.0 volts.
• | When the BCM monitors a low reference voltage of less than 4.5 volts. |
• | When the BCM monitors a high reference voltage of greater than 5.5 volts. |
• | When the BCM monitors a signal voltage of equal or greater than 4.86 volts for more than 1 second. |
The instrument panel illumination lamp dimming will not operate.
• | 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 DTC(s) can be cleared using a scan tool. |
The numbers below refer to the step numbers on the diagnostic table.
Tests for the proper operation of the circuit in the low voltage range.
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
Tests for a short to voltage in the 5 volt reference circuit.
Tests for a high resistance or an open in the low reference circuit.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics | ||||
1 | Did you perform the Lighting Systems Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the scan tool indicate that the Dimming Input data parameter is within the specified range? | 4.5 V - 5.5 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
Does the scan tool indicate that the Dimming Input data parameter is less than the specified value? | 4.5 V | Go to Step 4 | Go to Step 10 | |
Does the scan tool indicate that the Dimming Input data parameter is greater than the specified value? | 4.86 V | Go to Step 5 | Go to Step 8 | |
Does the voltage measure less than the specified value? | 5.15 V | Go to Step 6 | Go to Step 7 | |
Does the resistance measure less than the specified value? | 5 ohms | Go to Step 12 | Go to Step 11 | |
7 | Test the 5 volt reference circuit of the IP dimmer/headlamp switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
8 | Test the 5 volt reference circuit of the IP dimmer/headlamp switch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 9 |
9 | Test the signal circuit of the IP dimmer/headlamp switch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
10 | Test the signal circuit of the IP dimmer/headlamp switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
11 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the IP dimmer/headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 |
13 | Inspect for poor connections at the harness connector of the body control module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
14 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
15 |
Important: Perform the setup procedure for the BCM. Replace the body control module (BCM). Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 16 | -- |
16 |
Does the DTC reset? | -- | Go to Step 2 | System OK |