Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

Ignition/vehicle OFF, disconnect the connector at the S33 Steering Wheel Horn Contact.
Verify a test lamp illuminates between ground circuit terminal 1 and B+.
- If the test lamp does not illuminate
1. Repair the open/high resistance on circuit 1351 or the ground connection.
- Go to next step: If the test lamp illuminates
Ignition/vehicle On.
Verify the P12A Horn - High Note & P12B Horn - Low Note are not Active
- If Active
1. Test the circuit 3287 for a short to ground
  - If a short to ground is found, repair the fault on the circuit.
  - Go to next step: If a short to ground is not found.
2. Replace the K9 Body Control Module.
- Go to next step: If Inactive
Momentarily install a 3 A fused jumper wire between the signal circuit terminal 2 and ground.
Verify the P12A Horn - High Note & P12B Horn - Low Note are Active
- If the components do not sound and the 3 A fuse is OK
1. Test the circuit 3287 for an open/high resistance.
  - If an open/high resistance is found, repair the fault on the circuit.
  - Go to next step: If an open/high resistance is not found.
2. Replace the K9 Body Control Module.
- If the components do not sound and the 3 A fuse is open
1. Test the circuit 3287 for a short to voltage.
  - If a short to voltage is found, repair the fault on the circuit.
  - Go to next step: If a short to voltage is not found.
2. Replace the K9 Body Control Module.
- Go to next step: If the components produces a sound
Test or replace the S33 Steering Wheel Horn Contact.