Circuit/System Verification

2019 Chevrolet Tahoe LS, 4WD, Gas/EthanolSECTION Circuit/System Verification
WARNING: This page is about a different car, the 2018 Chevrolet Sonic. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:

Refer to HVAC System Malfunction  before performing this procedure

  1. Ignition ON, press and release the A/C Switch.
  2. Verify the scan tool HVAC A/C Switch parameter changes between Active and Inactive.
    • If the parameter does not change 

      Replace the K33 HVAC Control Module.

    • Go to next step: If the parameter changes 
  3. Set A/C system to coolest setting with blower ON.
  4. Press and release the A/C switch several times.
  5. Verify the scan tool ECM A/C Request Signal parameter changes between Active and Inactive.
    • If the parameter does not change 

      Replace the K33 HVAC Control Module.

    • Go to next step: If the parameter changes 
  6. Verify the A/C compressor clutch engages when commanding the ECM A/C Relay output function On and Off with a scan tool.
    • Go to next step: If the A/C compressor clutch engages 
  7. All OK.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.