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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 339 (Horn System) >> Diagnostic Information and Procedures >> DTC B2750: Horn Relay Secondary >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia. 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:P12L Horn - Left & P12R Horn - Right

    • If the component does not turn On and Off 
    1. Ignition/Vehicle » Off & Remove » Jumper wire(s)
    2. Disconnect the electrical connector: X1 X50A 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 26 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
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