AutoCodes – GMC – B2620 GMC

B2620 GMC Code - Display Dimming Pulse Width Modulation Input Circuit

Quick Answer

The Body Control Module (BCM) directly sends a 5-volt reference voltage to the Instrument Panel (I/P) dimmer switch which is then adjusted based on the I/P dimmer switch position and returned as a dimming return and dimming input to the BCM. Common causes include Faulty Headlamp Switch, Headlamp Switch harness is open or shorted, Headlamp Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B2620 GMC indicates Display Dimming Pulse Width Modulation Input Circuit.
Common causes: Common causes include Faulty Headlamp Switch, Headlamp Switch harness is open or shorted, Headlamp Switch circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,387

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jan 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B2620 GMC Description

The Body Control Module (BCM) directly sends a 5-volt reference voltage to the Instrument Panel (I/P) dimmer switch which is then adjusted based on the I/P dimmer switch position and returned as a dimming return and dimming input to the BCM. The BCM uses this signal to directly control the desired level of instrument panel illumination lamp intensity.

OBDII Code B2620 GMC - Display Dimming Pulse Width Modulation Input Circuit - AutoCodes.com — B2620 GMC Code - Display Dimming Pulse Width Modulation Input Circuit

What does this mean?

What are the Possible Causes of the DTC B2620 GMC?

Faulty Headlamp Switch
Headlamp Switch harness is open or shorted
Headlamp Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B2620 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B2620 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B2620 GMC code?

Need more information on how to fix the B2620 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B2620 GMC Code

1. What are the common symptoms of OBDII code B2620 GMC?

- Dim or flickering display on the vehicle's dashboard, inconsistent backlighting, and difficulty reading information on the screen.

2. What causes the Display Dimming Pulse Width Modulation Input Circuit issue (B2620 GMC)?

- The most common cause is a malfunction in the PWM (Pulse Width Modulation) module, a faulty wiring connection, or a damaged display unit.

3. How can I diagnose the B2620 GMC code?

- Start by checking the wiring connections to the display unit, testing the PWM module for proper functionality, and inspecting the display for any physical damage.

4. Can I continue driving my vehicle with the B2620 GMC code?

- It is generally safe to continue driving, but it is recommended to address the issue promptly to avoid potential safety hazards and further electrical problems.

5. What are some repair tips for fixing the Display Dimming Pulse Width Modulation Input Circuit problem?

- Repair options may include replacing the faulty PWM module, repairing any damaged wiring, or replacing the display unit if necessary.

6. Are there any DIY fixes for the B2620 GMC code?

- DIY fixes may be limited due to the complexity of the electrical system involved. It is best to consult a professional mechanic for an accurate diagnosis and repair.

7. How much does it cost to repair the B2620 GMC code?

- Repair costs can vary depending on the specific cause of the issue, but it may range from $100 to $500, including parts and labor.

8. Can a faulty battery or alternator cause the B2620 GMC code?

- While a weak battery or alternator can cause electrical issues, they are not common culprits for the Display Dimming Pulse Width Modulation Input Circuit problem.

9. Will resetting the OBDII code B2620 GMC make the issue go away?

- Resetting the code may temporarily clear the warning light, but it will not fix the underlying problem causing the display dimming issue.

10. Is the B2620 GMC code specific to certain GMC vehicle models?

- The B2620 code may be specific to certain GMC models, so it is recommended to check the vehicle's specific diagnostic manual for accurate information.