how to fix GMC Sierra T1XX (2019-Present) air conditioning not working

GMC Sierra T1XX (2019-Present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

534 words

Problem Statement

Learn how to diagnose and fix the air conditioning not working 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 handling any components near the engine.

Symptoms

•No cold air blowing from the A/C vents
•A/C compressor not engaging
•Unusual noises coming from the A/C system
•A/C system blowing warm air
•A/C warning light illuminated on the dashboard

Diagnostic Steps

1
Check the A/C system for any visible leaks.
2
Scan for error codes using an OBD-II scanner to identify potential issues.
3
Inspect the A/C fuse and relay for any damage or failure.
4
Measure the refrigerant levels using a manifold gauge set.
5
Check the A/C compressor for proper electrical connections and functionality.
6
Inspect the cabin air filter for clogs or restrictions.

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
•Multimeter
•Manifold gauge set
•Socket set
•Screwdriver set

Parts Required

•A/C fuse (if blown)
•A/C relay (if faulty)
•Refrigerant (R-134a)
•Cabin air filter

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Diagnostic Steps

1
Check the A/C system for any visible leaks.
2
Scan for error codes using an OBD-II scanner to identify potential issues.
3
Inspect the A/C fuse and relay for any damage or failure.
4
Measure the refrigerant levels using a manifold gauge set.
5
Check the A/C compressor for proper electrical connections and functionality.
6
Inspect the cabin air filter for clogs or restrictions.

Solution

1. Preparation

Gather tools and parts needed for the repair.
Ensure the vehicle is parked on a flat surface and the engine is off.
Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace A/C Fuse/Relay

Locate the fuse box under the dashboard or hood.
Remove the A/C fuse and inspect it for continuity using a multimeter.
If blown, replace with a fuse of the same amperage.
Check the A/C relay; if faulty, replace it with a new relay.

3. Recharge A/C System

Connect the manifold gauge set to the high and low-pressure service ports of the A/C system.
Check the refrigerant levels; if low, use the correct refrigerant type (usually R-134a).
Following the instructions on the refrigerant can, add refrigerant until the levels are within the manufacturer's specified range.
Monitor the system as it charges to ensure proper operation.

4. Inspect A/C Compressor

Reconnect the battery and start the engine.
Turn the A/C system to the maximum setting and check if the compressor engages.
If not, inspect the electrical connections to the compressor for damage.
If the compressor does not engage, it may require replacement.

5. Replace Cabin Air Filter

Locate the cabin air filter compartment, usually behind the glove box.
Remove the glove box to access the filter.
Remove the old cabin air filter and replace it with a new one, ensuring proper orientation.