GMC Sierra T1XX (2019-Present) AC not blowing cold air, what could be the problem?

GMC Sierra T1XX (2019-Present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

517 words

Problem Statement

Learn how to diagnose and fix AC not blowing cold air in GMC Sierra T1XX. 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 battery before working on electrical systems.
•Allow the engine to cool before removing any components near the radiator or AC system.

Symptoms

•AC compressor not engaging
•Warm air blowing from vents
•Unusual noises coming from the AC system
•Refrigerant leaks visible around AC components
•AC system cycling on and off rapidly
•Reduced airflow from AC vents

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for related faults.
2
Inspect the AC compressor for physical damage or signs of leakage.
3
Check the refrigerant level with a manifold gauge set to confirm it is within specifications.
4
Test the AC relay and fuses for continuity.
5
Verify the operation of the AC clutch when the system is turned on.
6
Inspect the cabin air filter for blockages that may restrict airflow.

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

•OBD-II scanner
•Manifold gauge set
•Multimeter
•Screwdriver set

Parts Required

•Refrigerant (R-134a)
•AC clutch relay
•Cabin air filter

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for related faults.
2
Inspect the AC compressor for physical damage or signs of leakage.
3
Check the refrigerant level with a manifold gauge set to confirm it is within specifications.
4
Test the AC relay and fuses for continuity.
5
Verify the operation of the AC clutch when the system is turned on.
6
Inspect the cabin air filter for blockages that may restrict airflow.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked on a level surface and the engine is turned off.
Disconnect the battery (negative terminal) for safety.

2. Check and Recharge Refrigerant

Tools Required: Manifold gauge set, refrigerant (R-134a).
Steps:
1. Connect the low-pressure side of the manifold gauge to the AC service port.
2. Start the engine and turn on the AC to the maximum setting.
3. Read the pressure on the gauge; if it’s below recommended levels, proceed to recharge.
4. Add refrigerant slowly until the pressure reaches the specified range (typically 30-40 psi for low side).
5. Disconnect the manifold gauge and securely replace the service port cap.

3. Inspect and Replace AC Clutch Relay

Tools Required: Multimeter, replacement relay.
Steps:
1. Locate the AC relay in the fuse box (refer to the owner's manual for exact location).
2. Remove the relay and test for continuity using a multimeter.
3. If faulty, replace with a new relay and ensure it is properly seated.

4. Test and Replace Cabin Air Filter

Tools Required: Screwdriver (if necessary).
Steps:
1. Locate the cabin air filter compartment (usually behind the glove box).
2. Remove the glove box if needed to access the filter.
3. Inspect the filter; if dirty or clogged, replace with a new filter.
4. Reassemble the glove box and ensure it operates smoothly.