how to fix GMC Sierra T1XX (2019-Present) AC not blowing air

GMC Sierra T1XX (2019-Present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

555 words

Problem Statement

Learn how to diagnose and fix AC not blowing air in GMC Sierra T1XX (2019-Present). Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on any electrical components.
•Allow the engine to cool before opening any components to avoid burns.

Symptoms

•No airflow from the AC vents
•AC control panel lights may be illuminated
•Unusual noises from the AC compressor or blower motor
•Warm air blowing from vents instead of cold air
•AC system not responding to temperature adjustments

Diagnostic Steps

1
Inspect the AC control settings to ensure the system is set to the correct mode.
2
Check the blower motor fuse in the fuse box for continuity.
3
Use an OBD-II scanner to check for any fault codes related to the HVAC system.
4
Inspect the blower motor for functionality by applying direct power to it.
5
Verify the AC refrigerant level and check for leaks in the system.
6
Examine the cabin air filter for blockage or excessive dirt.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•Screwdriver set
•Multimeter
•OBD-II scanner

Parts Required

•Replacement cabin air filter
•Blower motor (if defective)
•AC refrigerant (if low)

Related Faults

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Diagnostic Steps

1
Inspect the AC control settings to ensure the system is set to the correct mode.
2
Check the blower motor fuse in the fuse box for continuity.
3
Use an OBD-II scanner to check for any fault codes related to the HVAC system.
4
Inspect the blower motor for functionality by applying direct power to it.
5
Verify the AC refrigerant level and check for leaks in the system.
6
Examine the cabin air filter for blockage or excessive dirt.

Solution

1. Preparation

Tools Required:
- Screwdriver set
- Multimeter
- OBD-II scanner
- Replacement cabin air filter (if needed)
Disconnect the vehicle battery to ensure safety while working on electrical components.

2. Check Blower Motor Fuse

Locate the fuse box, typically found under the dashboard or in the engine bay.
Identify the fuse for the blower motor using the diagram on the fuse box cover.
Remove the fuse and inspect it for continuity using a multimeter. Replace if blown.

3. Inspect the Blower Motor

Remove the access panel to the blower motor, usually located under the dashboard on the passenger side.
Disconnect the electrical connector from the blower motor.
Use a multimeter to test for voltage at the connector when the AC is turned on.
If voltage is present but the motor does not operate, remove the blower motor and replace it.

4. Check AC Refrigerant Level

Locate the low-pressure service port on the AC system.
Connect a refrigerant gauge to check the pressure. If low, add the appropriate refrigerant (R-134a or R-1234yf depending on the model).
Inspect for visible signs of leaks around hoses and connections.

5. Replace Cabin Air Filter

Locate the cabin air filter compartment, usually behind the glove box.
Open the compartment and remove the old filter.
Install the new cabin air filter, ensuring the airflow direction matches the diagram on the filter.