my GMC Sierra T1XX (2019-Present) has a strange odor when I turn on the heater, what's the issue?

Learn how to diagnose and fix strange odors from the heater in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and turn off the ignition.
• Disconnect the battery to ensure safety while working on electrical components.

2. Cabin Air Filter Replacement

• Tools Required: Screwdriver, replacement cabin air filter.
• Sub-steps:
  1. Locate the cabin air filter access panel, typically found behind the glove box.
  2. Remove the glove box by unscrewing the retaining screws and disconnecting any electrical connectors.
  3. Open the access panel and remove the old cabin air filter.
  4. Inspect the area for dirt or debris, clean if necessary, and install the new filter according to the airflow direction indicated.

3. Heater Core Inspection

• Tools Required: Socket set, coolant catch pan.
• Sub-steps:
  1. Locate the heater core hoses in the engine bay and inspect for leaks.
  2. If leaks are found, clamp the hoses and remove them from the heater core.
  3. Use a coolant catch pan to capture any residual fluid.
  4. Inspect the heater core for signs of corrosion or blockage; replace if necessary.

4. HVAC System Cleaning

• Tools Required: HVAC cleaning solution, spray nozzle.
• Sub-steps:
  1. Obtain an HVAC cleaning solution specifically designed for automotive use.
  2. With the engine running and the heater on, spray the solution into the air intake while the system is set to recirculate.
  3. Allow the HVAC system to run for a few minutes to clear any mildew or mold.

5. Reassembly

• Reattach any components removed during the inspection.
• Reconnect the battery and ensure all connections are secure.