• | 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 each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Horn Relay Control | B2750 00 | B2750 00 | B2750 00 | -- |
Horn Control | 2 | 2 | 1 | -- |
Horn Switch Ground | -- | 2 | 2 | -- |
Horn Ground | -- | 2 | 2 | -- |
1. Horn Always On 2. Horn Inoperative |
The body control module (BCM) controls the horn relay by grounding the control circuit of the horn relay coil energizing the relay. When the horn relay is energized, the horn relay contacts close applying voltage through the horn fuse and the horn control circuit to the horns.
When the output is actively being requested by the BCM.
The BCM detects a short to ground, open or short to battery in the horn relay control circuit for approximately 125 milliseconds.
The BCM disables the output to the horn relay until the next ignition cycle.
• | The DTC clears when the fault is no longer detected. |
• | The current DTC will become history when the request for the output is removed. |
• | The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred. |
Horns System Description and Operation
Control Module References for scan tool information
Command the horn ON and OFF with the scan tool. The horn should turn ON and OFF when changing between the commanded states.
⇒ | If the test lamp is always ON, test the control circuit for a short to ground or a sticking horn switch. If the circuit tests normal, replace the BCM. |
⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage, an open high resistance, or a horn switch which is not closing. If the circuit tests normal, replace the BCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup and programming |