Circuit Description
When the body control module (BCM) receives a ground signal from the headlamp dimmer switch high beam signal circuit or flash-to-pass switch signal circuit requesting to illuminate the high beam headlamps, the BCM will energize the high beam relay by grounding the headlamp high 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. |
| • | Headlamp switch is in the ON position. |
| • | Headlamp high beam switch is cycled between high beams ON and OFF several times. |
Conditions for Setting the DTC
| • | When the BCM does not activate the high beam relay and the headlamp high beam relay control circuit is shorted to ground |
| • | When the BCM activates the high beam relay and the headlamp high beam 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 high 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 headlamp high beam relay control circuit of the high beam relay for the following:
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 poor connections at the harness connector of the high beam headlamp 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 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 14 | Go to Step 13 | ||||||
10 | Inspect for poor connections 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 fuse block. Refer to Underhood Electrical Center or Junction Block Replacement . Did you complete the replacement? | Go to Step 14 | -- | ||||||
12 | Replace the high beam headlamp relay in the underhood fuse block. Refer to Relay Replacement . Did you complete the replacement? | 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 | ||||||
