GMC Sierra T1XX (2019-Present) AC blows warm air, how can I fix it?

Learn how to diagnose and fix AC blowing warm air in GMC Sierra T1XX. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, manifold gauge set, multimeter, socket set, torque wrench.
• Disconnect the battery to ensure safety during repairs.

2. Check and Recharge Refrigerant

1. Connect Manifold Gauge Set: Attach the low and high-pressure hoses to the respective ports on the AC system.
2. Read Pressure Levels: Check the pressure readings; low pressure indicates low refrigerant.
3. Add Refrigerant: If low, add the appropriate refrigerant (R-134a or R-1234yf, depending on the system) according to the manufacturer's specifications.
4. Monitor System: Start the engine and turn on the AC to check if it begins to cool.

3. Inspect and Replace AC Compressor

1. Remove AC Compressor:
   • Disconnect the electrical connectors and the refrigerant lines.
   • Unbolt the compressor from its mounting brackets.
2. Install New Compressor:
   • Position the new compressor and secure it with bolts to the mounting brackets.
   • Reconnect the refrigerant lines and electrical connectors.
3. Recheck Refrigerant Levels: Ensure proper amounts are added after the replacement.

4. Check AC Control Module

1. Inspect Wiring: Look for any frayed or damaged wiring to the AC control module.
2. Test Module: Use a multimeter to check for proper voltage and ground at the module.
3. Replace Module if Faulty: If the module is not functioning correctly, replace it with a new unit.