Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Verification
2019 Chevrolet Trax Premier, AWDSECTION Circuit/System Verification
WARNING: This page is about a different car, the 2018 Chevrolet Trax and 2018 Buick Encore. 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.
- Ignition ON, press and release the A/C Switch.
- Verify the HVAC control module scan tool A/C Switch parameter changes between Active and Inactive.
- If the parameter does not change
Replace the A26 HVAC Controls.
- Go to next step: If the parameter changes
- If the parameter does not change
- Set A/C system to coolest setting with blower ON.
- Press and release the A/C switch several times.
- Verify the engine control module (ECM) scan tool 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
- If the parameter does not change
- Verify the A/C compressor clutch engages when commanding the engine control module (ECM) A/C Relay output function On and Off with a scan tool.
- If the A/C compressor clutch does not engage
Refer to DTC P0645, P0646, or P0647
- Go to next step: If the A/C compressor clutch engages
- If the A/C compressor clutch does not engage
- 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.