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Home >> Chevrolet >> 2018 >> Spark LT, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 97 (Horn System) >> Diagnostic Information and Procedures >> DTC B2750: Horn Relay Secondary Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: K9 Body Control Module
  3. Ignition - On / Vehicle - In Service Mode
  4. Momentarily connect a 3 A fused jumper wire between the test points: Control circuit terminal 19 X5 & Ground

    Verify the component turns On and Off when connecting and disconnecting the jumper wire: P12 Horn

    • If the component does not turn On and Off 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: X1X50A Fuse Block - Underhood
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 19 X5 @ Control module harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for infinite resistance between the test points: Control circuit terminal 19 X5 @ Control module harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance
    7. Test for less than 2 Ω between the test points: Control circuit terminal 19 X5 @ Control module harness & Terminal 21 X1 @ Fuse Block Harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω - Test or replace the component: X50A Fuse Block - Underhood
    • If the component turns On and Off 
  5. Replace the component: K9 Body Control Module