AutoCodes – GMC – B3806 GMC

B3806 GMC Code - High Beam and Headlamp Flash Select Circuit Malfunction

Quick Answer

When the turn signal/multifunction switch is momentarily placed in the flash-to-pass position, ground is applied to the Body Control Module (BCM) through the flash-to-pass signal circuit. Common causes include Faulty Turn Signal/Multifunction Switch, Turn Signal/Multifunction Switch harness is open or shorted, Turn Signal/Multifunction 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: B3806 GMC indicates High Beam and Headlamp Flash Select Circuit Malfunction.
Common causes: Common causes include Faulty Turn Signal/Multifunction Switch, Turn Signal/Multifunction Switch harness is open or shorted, Turn Signal/Multifunction 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 748

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 Jun 14, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3806 GMC Description

When the turn signal/multifunction switch is momentarily placed in the flash-to-pass position, ground is applied to the Body Control Module (BCM) through the flash-to-pass signal circuit. The BCM responds to the flash-to-pass request by applying ground to the high-beam relay control circuit which energizes the high-beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the high beam fuses to the high beam control circuits illuminating the high beam headlamps. The high beam headlamps will only illuminate for as long as the flash-to-pass switch is activated. The Diagnostic Trouble Code (DTC) sets when the BCM detects a short to ground in the turn signal/multifunction switch flash to pass signal circuit.

OBDII Code B3806 GMC - High Beam and Headlamp Flash Select Circuit Malfunction - AutoCodes.com — B3806 GMC Code - High Beam and Headlamp Flash Select Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC B3806 GMC?

Faulty Turn Signal/Multifunction Switch
Turn Signal/Multifunction Switch harness is open or shorted
Turn Signal/Multifunction Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3806 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 B3806 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 B3806 GMC code?

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Need Help with the Code?

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Information for Specific GMC Models

B3806 2014 GMC Sierra — High Beam and Headlamp Flash Select Circuit Malfunction
B3806 2015 GMC Sierra — High Beam and Headlamp Flash Select Circuit Malfunction
B3806 2016 GMC Sierra — High Beam and Headlamp Flash Select Circuit Malfunction
B3806 2017 GMC Sierra — High Beam and Headlamp Flash Select Circuit Malfunction
B3806 2018 GMC Sierra — High Beam and Headlamp Flash Select Circuit Malfunction

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 B3806 GMC Code

1. What are the common symptoms of OBDII code B3806 GMC (High Beam and Headlamp Flash Select Circuit Malfunction)?

- The common symptoms include malfunctioning high beams, issues with headlamp flashing, and the illumination of the check engine light.

2. What are the possible causes of OBDII code B3806 GMC?

- The possible causes include a faulty high beam switch, damaged wiring or connectors in the headlamp circuit, or a defective body control module.

3. How can I diagnose OBDII code B3806 GMC?

- Diagnosing this code typically involves using a scan tool to retrieve the specific fault code, checking the high beam switch functionality, inspecting wiring for damage, and testing the body control module.

4. Can I continue driving my vehicle with OBDII code B3806 GMC?

- It is not recommended to continue driving with this code as it can affect the proper operation of your high beams and headlamp flashing, compromising visibility and safety.

5. How can I repair OBDII code B3806 GMC?

- Repairing this code may involve replacing the high beam switch, repairing or replacing damaged wiring or connectors, or reprogramming the body control module if necessary.

6. Are there any DIY tips for addressing OBDII code B3806 GMC?

- DIY tips may include visually inspecting wiring for damage, checking fuses related to the headlamp circuit, and ensuring the high beam switch is functioning correctly.

7. Can weather conditions impact OBDII code B3806 GMC?

- Extreme weather conditions like excessive moisture or temperature fluctuations can potentially affect the electrical components involved, leading to the triggering of this fault code.

8. How long does it typically take to repair OBDII code B3806 GMC?

- The repair time can vary depending on the exact cause of the issue, but it may take anywhere from a few hours to a full day to diagnose and fix the problem.

9. Is it necessary to reset the fault code after repairing OBDII code B3806 GMC?

- Yes, it is important to clear the fault code using a scan tool after completing the repairs to ensure the check engine light is reset and the issue is resolved.

10. Will OBDII code B3806 GMC cause my vehicle to fail an emissions test?

- If left unresolved, this code may cause your vehicle to fail an emissions test, as it indicates a malfunction in the headlamp circuit that can impact overall vehicle performance.