Circuit/System Testing
WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.
Horn Switch Malfunction
- Ignition OFF and all vehicle systems OFF, disconnect the X1 and X2 harness connectors at the S33 Horn switch. It may take up to 2 min for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal 1 X1 and ground.
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- If less than 10 Ω
- Ignition ON.
- Verify the scan tool Horn Switch parameter is Inactive.
- If not Inactive
- Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
- Test for infinite resistance between the signal circuit terminal 1 X2 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K9 Body Control Module.
- If Inactive
- Install a 3 A fused jumper wire between the signal circuit terminal 1 X2 and ground.
- Verify the scan tool Horn Switch parameter is Active.
- If not Active
- Ignition OFF, remove the jumper wire, disconnect the harness connector at the K9 Body Control Module, ignition ON.
- Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- If Active
- Test or replace the S33 Horn Switch.
Horns or Horn Command Malfunction
- Ignition OFF, and all vehicle systems OFF. Disconnect the harness connector at the P12 Horn. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 1 Ω between the ground circuit terminal 1 and ground.
- If 1 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- If less than 1 Ω
- Connect a test lamp between the control circuit terminal 2 and ground, ignition ON.
- Verify the test lamp does not turn ON and OFF when commanding the Horn Relay On and Off with a scan tool.
- If the test lamp turns ON and OFF
Test or replace the P12 Horn.
- If the test lamp does not turn ON and OFF
- If the test lamp turns ON and OFF
- Ignition OFF, connect the harness connector at the P12 Horn. Disconnect the X1 harness connector at the X50A Fuse Block-Underhood, ignition ON.
- Verify the P12 Horn is not activated.
- If the P12 Horn is activated
- Ignition OFF, disconnect the harness connector at the P12 Horn, ignition ON.
- Test for less than 1 V between the control circuit terminal 2 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, test or replace the P12 Horn.
- If the P12 Horn is not activated
- Connect a 15 A fused jumper wire between the control circuit terminal D4 and B+.
- Verify the P12 Horn activates.
- If the P12 Horn does not activate
- Ignition OFF, remove the jumper wire, disconnect the harness connector at the P12 Horn, ignition ON.
- Test for infinite resistance between the control circuit and ground.
- If less than Infinite resistance, repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, test or replace the P12 Horn.
- If the P12 Horn activates
- Ignition OFF, connect the X1 harness connector at the X50A Fuse Block-Underhood. Disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
- Verify the P12 Horn is not activated.
- If the P12 Horn is activated
- Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block-Underhood.
- Test for infinite resistance between the control circuit terminal 19 X5 at the K9 Body Control Module and ground.
- If less than Infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the X50A Fuse Block-Underhood.
- If the P12 Horn is not activated
- Connect a 3 A fused jumper wire between the control circuit terminal 19 and ground.
- Verify the P12 Horn activates.
- If the P12 Horn does not activate
- Ignition OFF, remove the jumper wire, disconnect the X2 harness connector at the X50A Fuse Block-Underhood, ignition ON.
- Test for less than 1 V between the control circuit terminal 19 X5 at the K9 Body Control Module and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the X50A Fuse Block-Underhood.
- If the P12 Horn activates
- Replace the K9 Body Control Module.
Horn - Poor Tone
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the P12 Horn. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 1 Ω between the ground circuit terminal 1 and ground.
- If 1 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the high resistance in the circuit.
- If less than 2 Ω, repair high resistance in the ground connection.
- If less than 1 Ω
- Ignition OFF, disconnect the X1 harness connector at the X50A Fuse Block-Underhood.
- Test for less than 2 Ω between the P12 Horn control circuit terminal 2 and the X50A Fuse Block-Underhood control circuit terminal D4 X1.
- If 2 Ω or greater
Repair the high resistance in the control circuit.
- If less than 2 Ω
- If 2 Ω or greater
- Test or replace the P12 Horn.