AutoCodes – GMC – B3806 2018 GMC Sierra

B3806 2018 GMC Sierra 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 2018 GMC Sierra 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 167

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 2018 GMC Sierra 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 2018 GMC Sierra - High Beam and Headlamp Flash Select Circuit Malfunction - AutoCodes.com — B3806 2018 GMC Sierra Code - High Beam and Headlamp Flash Select Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC B3806 2018 GMC Sierra?

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 2018 GMC Sierra?

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 2018 GMC Sierra 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 2018 GMC Sierra code?

Need more information on how to fix the B3806 2018 GMC Sierra 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 B3806 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code B3806 in a 2018 GMC Sierra?

- Common symptoms include malfunctioning high beam headlights, headlamp flash not working, and dashboard warning light indicating a circuit malfunction.

2. What does the OBDII code B3806 indicate in a 2018 GMC Sierra?

- The code B3806 indicates a High Beam and Headlamp Flash Select Circuit Malfunction in the vehicle's lighting system.

3. What are some possible causes of the B3806 OBDII code in a 2018 GMC Sierra?

- Potential causes include a faulty high beam switch, damaged wiring or connectors in the headlamp circuit, or a malfunctioning control module.

4. How can I diagnose the B3806 OBDII code in my 2018 GMC Sierra?

- To diagnose the issue, you may need to visually inspect the wiring and connectors, test the high beam switch for proper functioning, and use a diagnostic scanner to read the code and check for related faults.

5. Can I still drive my 2018 GMC Sierra with the B3806 OBDII code?

- While the vehicle may still be operable, it is recommended to address the issue promptly to ensure proper functioning of the high beam headlights and headlamp flash.

6. How can I repair the High Beam and Headlamp Flash Select Circuit Malfunction in my 2018 GMC Sierra?

- Repairing the issue may involve replacing a faulty high beam switch, repairing damaged wiring or connectors, or reprogramming the control module.

7. Is it safe to attempt DIY repairs for the B3806 OBDII code in a 2018 GMC Sierra?

- DIY repairs are possible for those with automotive repair experience, but if unsure, it is recommended to seek professional help to ensure proper diagnosis and repair.

8. How much can I expect to pay to fix the B3806 OBDII code in my 2018 GMC Sierra?

- Repair costs can vary based on the specific cause of the issue, but you may expect to pay anywhere from $100 to $500 for parts and labor, depending on the extent of the repair needed.

9. Will resetting the OBDII code B3806 in my 2018 GMC Sierra make the issue go away?

- Resetting the code may temporarily clear the dashboard warning light, but if the underlying issue is not addressed, the code is likely to reappear once the malfunction is detected again.

10. How can I prevent the recurrence of the B3806 OBDII code in my 2018 GMC Sierra?

- To prevent the code from reoccurring, ensure proper maintenance of the vehicle's lighting system, address any issues promptly, and follow recommended service schedules for your GMC Sierra.