FAULTBASE
Error CodesASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/GMC/Sierra/T1XX (2019-Present)/my GMC Sierra dashboard lights are dim what could be wrong

my GMC Sierra dashboard lights are dim what could be wrong

GMC Sierra T1XX (2019-Present)

Error Codes
Severity: mediumDifficulty: medium1-2 hours
3 min read
541 words

Problem Statement

Learn how to diagnose and fix dim dashboard lights in GMC Sierra. Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component
Electrical
Estimated Time
1-2 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical systems to prevent shorts.
  • ⚠Allow the engine to cool before inspecting any components.

Symptoms

  • •Dashboard lights are consistently dim
  • •Difficulty reading dashboard gauges at night
  • •Headlights may also appear dim
  • •Possible flickering of dashboard lights
  • •Battery warning light may illuminate
  • •Electrical accessories may function poorly

Diagnostic Steps

  1. 1Inspect the dimmer switch for functionality and ensure it's not set to the lowest setting.
  2. 2Use an OBD-II scanner to check for any error codes related to the electrical system or battery.
  3. 3Check the vehicle's battery voltage using a multimeter; it should read around 12.6 volts with the engine off.
  4. 4Inspect all fuses related to the dashboard and interior lighting for any signs of failure.
  5. 5Examine wiring and connectors for corrosion or loose connections behind the dashboard and at the battery.
  6. 6Test the alternator output while the engine is running; it should read between 13.7 to 14.7 volts.

Solution

Solution

1. Preparation

  • Gather all necessary tools and parts.
  • Ensure the vehicle is parked on a level surface, with the engine off, and the keys removed from the ignition.
  • Disconnect the battery (-) terminal to prevent any electrical shorts.

2. Inspect the Dimmer Switch

  • Remove the trim panel surrounding the dashboard (if necessary) using a trim removal tool.
  • Locate the dimmer switch and ensure it operates smoothly without any obstructions.
  • If the switch is faulty, replace it with a new one.

3. Check Battery and Alternator

  • Reconnect the battery terminal.
  • Use a multimeter to check the battery voltage; if it's below 12.4 volts, consider replacing the battery.
  • Start the engine and measure the voltage at the battery terminals; if it is below 13.7 volts, replace the alternator.

4. Replace Fuses if Necessary

  • Locate the fuse box, usually under the dashboard or in the engine compartment.
  • Identify and remove any blown fuses related to the lighting system.
  • Replace with fuses of the same amperage rating.

5. Inspect Wiring and Connectors

  • Check all wiring leading to the dashboard for any signs of wear, fraying, or corrosion.
  • Clean any corroded connectors with electrical contact cleaner and reconnect securely.
  • If any wiring is damaged, repair or replace as necessary.

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
  • •Trim removal tool
  • •Socket set
  • •Electrical contact cleaner

Parts Required

  • •Dimmer switch (if faulty)
  • •Replacement fuses (if blown)
  • •Battery (if voltage is low)

Additional Information

Affected Component
Electrical
Estimated Time
1-2 hours
Difficulty
medium
Severity
medium
Tools Required
5 items
Parts Required
3 items

Related Faults

  1. why does my GMC Sierra T1XX (2019-Present) check engine light keep flashing

    Learn how to diagnose and fix a flashing check engine light on your GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

    Engine6 symptoms
  2. 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.

    HVAC5 symptoms
  3. how to replace the fuel filter in GMC Sierra T1XX (2019-Present)?

    Step-by-step guide to replacing the fuel filter in GMC Sierra T1XX (2019-Present). Learn symptoms, diagnostic steps, and safety precautions.

    Fuel System6 symptoms
  4. how to diagnose GMC Sierra T1XX (2019-Present) airbag warning light?

    Learn how to diagnose and fix the airbag warning light issue in GMC Sierra T1XX (2019-present). Step-by-step guide with diagnostic procedures and repair instructions.

    Electrical5 symptoms
  5. why does my GMC Sierra T1XX (2019-Present) make a hissing noise when starting?

    Discover the causes and solutions for hissing noise during engine start in GMC Sierra T1XX. Step-by-step diagnostic and repair guide included.

    Engine5 symptoms
  6. how to fix P0301 code in GMC Sierra T1XX (2019-Present)?

    Learn how to diagnose and fix P0301 cylinder 1 misfire in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

    P0301Engine5 symptoms

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation