AutoCodes – Buick – B3650 Buick

B3650 Buick Code - High Beam Request Signal Circuit Performance Signal Invalid

Quick Answer

When the low beam headlamps are on and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the Body Control Module (BCM) through the high beam 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: B3650 Buick indicates High Beam Request Signal Circuit Performance Signal Invalid.
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 449

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 B3650 Buick Description

When the low beam headlamps are on and the turn signal/multifunction switch is placed in the high beam position, ground is applied to the Body Control Module (BCM) through the high beam signal circuit. The BCM responds to the high beam 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 Diagnostic Trouble Code (DTC) sets when the BCM detects a short to ground in the turn signal/multifunction switch high beam signal circuit.

OBDII Code B3650 Buick - High Beam Request Signal Circuit Performance Signal Invalid - AutoCodes.com — B3650 Buick Code - High Beam Request Signal Circuit Performance Signal Invalid

What does this mean?

What are the Possible Causes of the DTC B3650 Buick?

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 B3650 Buick?

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 B3650 Buick 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.

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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 B3650 Buick Code

1. What does the OBDII code B3650 mean for a Buick?

The code B3650 indicates an issue with the high beam request signal circuit, specifically that the performance signal is invalid.

2. What are the common symptoms of the B3650 code?

Symptoms may include high beams not functioning, high beam indicator light not illuminating, or improper operation of the headlights.

3. What causes the B3650 code to be triggered?

Common causes include a faulty high beam switch, damaged wiring or connectors in the circuit, or a malfunctioning body control module (BCM).

4. Can a blown fuse cause the B3650 code?

Yes, a blown fuse in the headlight circuit can disrupt the high beam request signal and trigger this code.

5. How is the B3650 code diagnosed?

Diagnosis involves checking the high beam switch, inspecting wiring and connectors, testing the circuit with a multimeter, and scanning the BCM for additional codes.

6. Can I still drive my Buick with the B3650 code active?

While the car may still be drivable, the high beams may not work, which can be a safety hazard, especially at night or in low-visibility conditions.

7. How do I fix the B3650 code on my Buick?

Repairs may include replacing a faulty high beam switch, repairing damaged wiring or connectors, or reprogramming or replacing the BCM if necessary.

8. How much does it cost to repair the B3650 code?

Repair costs can range from $50 to $300, depending on the issue, such as replacing a switch or repairing wiring. BCM replacement could be more expensive.

9. Can a weak battery cause the B3650 code?

A weak or failing battery can cause electrical issues, but itâ€™s less likely to cause this specific code unless it affects the BCM or circuit voltage.

10. Does the B3650 code require professional repair?

While some repairs, like checking fuses or connectors, can be done by DIYers, diagnosing and repairing BCM or circuit issues often requires professional tools and expertise.