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

GMC Sierra T1XX (2019-Present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

642 words

Problem Statement

Learn how to diagnose and fix AC not blowing cold 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 electrical systems.
•Allow the engine to cool before working on the AC system.

Symptoms

•AC system blowing warm air
•Reduced airflow from the vents
•Unusual noises from the AC compressor
•AC system cycling on and off rapidly
•Moisture or water accumulation inside the cabin

Diagnostic Steps

1
Check the refrigerant levels using a manifold gauge set.
2
Inspect the AC compressor for proper operation and listen for unusual noises.
3
Examine the AC condenser for any blockages or damage.
4
Test the blower motor for proper functionality.
5
Scan the vehicle's OBD-II system for any related error codes.
6
Verify the operation of the AC control module and climate control settings.

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

•Manifold gauge set
•Recovery machine
•Socket set
•Wrench set
•Multimeter
•Cleaning solution
•Soft brush

Parts Required

•Refrigerant (R-134a or R-1234yf)
•AC compressor
•AC condenser
•Blower motor

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Diagnostic Steps

1
Check the refrigerant levels using a manifold gauge set.
2
Inspect the AC compressor for proper operation and listen for unusual noises.
3
Examine the AC condenser for any blockages or damage.
4
Test the blower motor for proper functionality.
5
Scan the vehicle's OBD-II system for any related error codes.
6
Verify the operation of the AC control module and climate control settings.

Solution

1. Preparation

Gather all necessary tools and parts.
Ensure the vehicle is parked on a level surface and the engine is off.
Disconnect the battery to ensure safety while working on electrical components.

2. Check and Recharge Refrigerant

Tools Required: Manifold gauge set, refrigerant (R-134a or R-1234yf as specified), recovery machine (if necessary).
Sub-steps:
1. Connect the manifold gauge set to the AC service ports (high and low).
2. Check the pressure readings against the manufacturer's specifications.
3. If low, recover any existing refrigerant using a recovery machine.
4. Recharge the system with the appropriate type and amount of refrigerant.
5. Run the AC system for a few minutes and check the pressures again.

3. Inspect and Replace AC Compressor

Tools Required: Socket set, wrench set, AC compressor replacement kit.
Sub-steps:
1. Locate the AC compressor and inspect wiring and connections.
2. Remove the serpentine belt from the AC compressor pulley.
3. Disconnect the AC lines from the compressor.
4. Unbolt and remove the AC compressor from its mounting.
5. Install the new compressor, ensuring proper torque specifications are followed (usually around 18-25 lb-ft).
6. Reconnect the AC lines and the serpentine belt.

4. Clean or Replace AC Condenser

Tools Required: Cleaning solution, soft brush, or replacement condenser.
Sub-steps:
1. Inspect the AC condenser for debris or damage.
2. Clean the condenser with a soft brush and cleaning solution if dirty.
3. If damaged, remove the old condenser by unbolting it from its mounts.
4. Install the new condenser, ensuring all connections are secure.

5. Test Blower Motor Operation

Tools Required: Multimeter.
Sub-steps:
1. Locate the blower motor, usually found under the dashboard.
2. Disconnect the blower motor connector and test for voltage using a multimeter.
3. If no voltage is present, trace back to the blower motor resistor or control module.
4. Replace the blower motor if it is malfunctioning.