AutoCodes – GMC – B3596 2018 GMC Sierra

B3596 2018 GMC Sierra Code - Hazard Lamps Request Circuit Malfunction

Quick Answer

The hazard flashers may be activated in any power mode. 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: B3596 2018 GMC Sierra indicates Hazard Lamps Request 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 168

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 13, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3596 2018 GMC Sierra Description

The hazard flashers may be activated in any power mode. The hazard warning switch signal circuit is momentarily grounded when the hazard warning switch is pressed. The Body Control Module (BCM) responds to the hazard warning switch signal input by supplying battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard warning switch is activated, the BCM sends a serial data message to the instrument cluster requesting both turn signal indicators to be cycled ON and OFF. The Diagnostic Trouble Code (DTC) sets when the BCM detects a short to ground in the hazard warning switch signal circuit.

OBDII Code B3596 2018 GMC Sierra - Hazard Lamps Request Circuit Malfunction - AutoCodes.com — B3596 2018 GMC Sierra Code - Hazard Lamps Request Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC B3596 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 B3596 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 B3596 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 B3596 2018 GMC Sierra 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 B3596 2018 GMC Sierra Code

1. What does the OBDII code B3596 mean on a 2018 GMC Sierra?

B3596 indicates a malfunction in the hazard lamps request circuit, which controls the activation of the hazard warning lights.

2. What are the common symptoms of code B3596 in a 2018 GMC Sierra?

Symptoms include hazard lights not turning on, hazard lights staying on continuously, or a warning light on the dashboard.

3. What causes the B3596 code to appear?

The code can be triggered by a faulty hazard switch, damaged wiring in the hazard lamp circuit, or a malfunctioning body control module (BCM).

4. Can a blown fuse cause the B3596 code?

Yes, a blown fuse in the hazard lamp circuit can interrupt power and trigger the B3596 code.

5. How do I diagnose the B3596 code?

Inspect the hazard switch, wiring, and connectors for damage or corrosion. Check for blown fuses and test the hazard lamp circuit for proper voltage and continuity.

6. Can I still drive my 2018 GMC Sierra with the B3596 code?

Yes, but your hazard lights may not function properly, which could be a safety concern in emergencies.

7. How do I fix the B3596 code on my GMC Sierra?

Repairs may include replacing the hazard switch, repairing damaged wiring, replacing a blown fuse, or reprogramming the BCM if necessary.

8. How much does it cost to repair the B3596 code?

Repair costs can vary but typically range from $50 to $300, depending on whether parts like the hazard switch or BCM need replacement.

9. Can a dead battery cause the B3596 code?

A dead or weak battery may cause electrical issues that could indirectly trigger the B3596 code, but it's not a common cause.

10. Do I need a professional to fix the B3596 code?

While experienced DIYers can handle basic wiring and switch replacements, complex issues like BCM reprogramming may require professional assistance.

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