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Tahoe / Yukon Service Manual

DTC B13E7

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 each diagnostic category. DTC Descriptor DTC B13E7 23 Horn Switch Signal Diagnostic Fault Information

Circuit number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
3287 Signal B13E7 23 1 — —
6051 Ground — 1 — —
1. S33 Steering Wheel Horn Contact= Inoperative

Circuit/System Description The K9 Body Control Module provides the S33 Steering Wheel Horn Contact with approximately 7.5V to the signal circuit 3287. When the switch is pressed, the K9 Body Control Module will detect the voltage drop in the signal circuit 3287 and will command the KR3 Horn Relay to energize. Conditions for Running the DTC When the output is actively being requested by the body control module. Conditions for Setting the DTC Circuit 3287 is stuck low Action Taken When the DTC Sets The horn will continuously sound until it is disconnected or when it overheats and becomes inoperative. Conditions for Clearing the DTC 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 40 consecutive fault-free ignition cycles have occurred. Reference Information Schematic Reference Horn Schematics Connector End View Reference Master Electrical Component List Description and Operation Horns System Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Electrical Relay Replacement Scan Tool Reference Control Module References Circuit/System Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Operate the component: S33 Steering Wheel Horn Contact » Pressed Verify the component turns On and Off: P13 Horn ⇒ If the component does not turn On and Off Refer to: Circuit/System Testing ⇓ If the component turns On and Off
  3. A fault is not currently present and may be an intermittent condition Circuit/System Testing
  4. Ignition/vehicle OFF, disconnect the connector at the S33 Steering Wheel Horn Contact.
  5. Verify a test lamp illuminates between ground circuit terminal 1 and B+. ⇒ If the test lamp does not illuminate 2.1. Repair the open/high resistance on circuit 6051 or the ground connection. ⇓ If the test lamp illuminates
  6. Ignition/vehicle On.
  7. Verify the P13 Horn is not Active ⇒ If Active 4.1. Test the circuit 3287 for a short to ground ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 4.2. Replace the K9 Body Control Module. ⇓ If Inactive
  8. Momentarily install a 3 A fused jumper wire between the signal circuit terminal 2 and ground.
  9. Verify the P13 Horn is Active ⇒ If the component does not sound and the 3 A fuse is OK 6.1. Test the circuit 3287 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 6.2. Replace the K9 Body Control Module. ⇒ If the component does not sound and the 3 A fuse is open 6.1. Test the circuit 3287 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 6.2. Replace the K9 Body Control Module. ⇓ If the component produces a sound
  10. Test or replace the S33 Steering Wheel Horn Contact. Component Testing
  11. Ignition/Vehicle » Off
  12. Disconnect the electrical connector: S33 Steering Wheel Horn Contact
  13. Test for infinite resistance between the test points: Signal terminal 2 & Ground terminal 1 — S33 Steering Wheel Horn Contact » Not Pressed ⇒ If less than infinite resistance Replace the component: S33 Steering Wheel Horn Contact ⇓ If infinite resistance
  14. Test for less than 3 Ω between the test points: Signal terminal 2 & Ground terminal 1 — S33 Steering Wheel Horn Contact » Pressed ⇒ If 3 Ω or greater Replace the component: S33 Steering Wheel Horn Contact ⇓ If less than 3 Ω
  15. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Steering Wheel Airbag Replacement For control module replacement, programming, and setup refer to: Control Module References