Circuit Description
When the body control module (BCM) receives a ground signal from the headlamp dimmer switch high beam signal or flash to pass (FTP) switch signal commanding to illuminate the high beam headlamps, the BCM will energize the high beam relay by grounding the HI BEAM relay control circuit.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2580 Headlamp High Beam Control Circuit
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | When the BCM receives a high beam headlamp OFF command and the high beam headlamp relay control circuit is shorted to ground. |
| • | When the BCM receives a high beam headlamp ON command and the high beam headlamp relay control circuit is shorted to voltage or open. |
Action Taken When the DTC Sets
The high beam headlamps will not operate or will remain always 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. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the HI BEAM relay turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 |
4 |
Does the test lamp turn ON and OFF with each command? | Go to Step 8 | Go to Step 5 |
5 | Does the test lamp remain illuminated with each command? | Go to Step 7 | Go to Step 6 |
6 | Test the control circuit of the HI BEAM relay for a short to battery positive voltage or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 9 |
7 | Test for a short to ground in the headlamp high beam relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 9 |
8 | Inspect for a high resistance or a poor connection at the HI BEAM relay in the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
9 | Inspect for a high resistance or a poor connection 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 14 | Go to Step 13 |
10 | Inspect for a high resistance or a poor connection at the harness connectors of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 11 |
11 | Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement . Did you complete the repairs? | Go to Step 14 | -- |
12 | Replace the HI BEAM relay in the underhood fuse block. Refer to Relay Replacement . Did you complete the repair? | Go to Step 14 | -- |
13 | Replace the BCM . Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | -- |
14 |
Does the DTC reset? | Go to Step 2 | System OK |
