my GMC Sierra T1XX (2019-Present) AC is not blowing cold air

GMC Sierra T1XX (2019-Present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

471 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 the battery before working on electrical systems.
•Use proper safety gear when handling refrigerants.

Symptoms

•AC compressor not engaging
•Warm air blowing from the vents
•Unusual noises from the AC system
•Frost build-up on the AC lines
•Increased humidity inside the cabin
•AC control panel lights not functioning

Diagnostic Steps

1
Check the AC system fuse using the vehicle’s fuse box diagram.
2
Use an OBD-II scanner to check for error codes related to the AC system.
3
Inspect the AC compressor visually for any signs of damage or leaks.
4
Measure the refrigerant pressure using a manifold gauge set.
5
Test the AC control switch operation and wiring continuity.
6
Examine the cabin air filter for clogs or obstructions.

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
•Socket set
•Torque wrench
•Screwdrivers

Parts Required

•AC compressor (if needed)
•R-134a refrigerant
•AC fuse (if needed)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Check the AC system fuse using the vehicle’s fuse box diagram.
2
Use an OBD-II scanner to check for error codes related to the AC system.
3
Inspect the AC compressor visually for any signs of damage or leaks.
4
Measure the refrigerant pressure using a manifold gauge set.
5
Test the AC control switch operation and wiring continuity.
6
Examine the cabin air filter for clogs or obstructions.

Solution

1. Preparation

Gather all necessary tools and parts.
Disconnect the battery to ensure safety while working on electrical components.

2. Check and Replace Fuses

Locate the fuse box and find the AC fuse.
Inspect the fuse for continuity; replace if blown with an equivalent amperage fuse.

3. Recharge Refrigerant

Connect the manifold gauge set to the AC service ports (high and low).
Check the low-pressure side reading (should be between 25-40 psi) and high-pressure side (should be between 200-250 psi).
If refrigerant is low, add the appropriate type of R-134a refrigerant until proper pressure is achieved.

4. Inspect and Replace AC Compressor

If the compressor is damaged, remove the serpentine belt and disconnect the electrical connector.
Unbolt the AC compressor from the mounting bracket and remove the refrigerant lines (ensure to recover refrigerant properly).
Install the new compressor, ensuring all seals are replaced and properly torqued to manufacturer specifications.
Reconnect refrigerant lines and electrical connectors.

5. Test the System

Reconnect the battery and start the engine.
Turn on the AC to the maximum setting and check for cold air and proper compressor function.