AutoCodes – Cadillac – B3949 Cadillac

B3949 Cadillac Code - Right Front Turn Signal Circuit

Quick Answer

Ground is applied at all times to the turn signal/multifunction switch. Common causes include Faulty Right Front Turn Signal Lamp, Right Front Turn Signal Lamp harness is open or shorted, Right Front Turn Signal Lamp 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: B3949 Cadillac indicates Right Front Turn Signal Circuit.
Common causes: Common causes include Faulty Right Front Turn Signal Lamp, Right Front Turn Signal Lamp harness is open or shorted, Right Front Turn Signal Lamp 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 903

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 17, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3949 Cadillac Description

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START positions. When the turn signal/multifunction switch is placed in either the TURN RIGHT or TURN LEFT position, ground is applied to the Body Control Module (BCM) through either the right turn or left turn signal switch signal circuit. The BCM responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument cluster requesting the respective turn signal indicator be pulsed ON and OFF. The Diagnostic Trouble Code (DTC) will be set when the BCM detects an open/high resistance in the left front turn signal control circuit.

OBDII Code B3949 Cadillac - Right Front Turn Signal Circuit - AutoCodes.com — B3949 Cadillac Code - Right Front Turn Signal Circuit

What does this mean?

What are the Possible Causes of the DTC B3949 Cadillac?

Faulty Right Front Turn Signal Lamp
Right Front Turn Signal Lamp harness is open or shorted
Right Front Turn Signal Lamp circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3949 Cadillac?

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 B3949 Cadillac 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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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 B3949 Cadillac Code

1. What are the common symptoms of OBDII code B3949 in a Cadillac related to the right front turn signal circuit?

- The common symptoms include the right front turn signal not functioning properly, rapid blinking of the turn signal, or a completely non-functional right front turn signal.

2. What are the possible causes of OBDII code B3949 in a Cadillac affecting the right front turn signal circuit?

- The possible causes may include a faulty right front turn signal bulb, a damaged wiring harness, a defective turn signal switch, or a malfunctioning Body Control Module (BCM).

3. How can I diagnose the OBDII code B3949 in a Cadillac for the right front turn signal circuit issue?

- You can start by visually inspecting the right front turn signal bulb for any visible damage. Check the wiring for any cuts or breaks, and test the turn signal switch and BCM using a multimeter for proper functionality.

4. Is it safe to continue driving with OBDII code B3949 related to the right front turn signal circuit in a Cadillac?

- It is not recommended to drive with malfunctioning turn signals as it can pose a safety hazard. It is best to address the issue promptly to ensure proper signaling for turning and changing lanes.

5. Are there any quick repair tips for resolving OBDII code B3949 in a Cadillac associated with the right front turn signal circuit?

- A quick repair tip is to start by replacing the right front turn signal bulb with a new one to see if that resolves the issue. Make sure to check the wiring connections and the turn signal switch as well.

6. Can a DIY enthusiast fix OBDII code B3949 in a Cadillac affecting the right front turn signal circuit?

- Depending on your level of expertise, you may be able to address simple issues like replacing the turn signal bulb or checking for loose connections. However, more complex problems may require professional diagnosis and repair.

7. How much does it typically cost to repair OBDII code B3949 in a Cadillac related to the right front turn signal circuit?

- The cost of repair can vary depending on the specific cause of the issue. Replacing a turn signal bulb can be relatively inexpensive, while fixing wiring or components like the BCM may cost more. It is advisable to obtain quotes from mechanics.

8. What other OBDII codes may be related to or triggered by B3949 in a Cadillac's right front turn signal circuit malfunction?

- Other related OBDII codes that may be triggered include codes related to turn signal circuit failures, such as B3948 (Left Front Turn Signal Circuit), B394A (Rear Turn Signal Circuit), or B394B (Hazard Switch Circuit).

9. Can extreme weather conditions or environmental factors contribute to triggering OBDII code B3949 in a Cadillac for the right front turn signal circuit?

- Yes, extreme weather conditions or exposure to moisture can potentially cause corrosion in the wiring or connections, leading to malfunctions in the right front turn signal circuit and triggering the OBDII code B3949.

10. Should I reset the OBDII code B3949 in a Cadillac after repairing the right front turn signal circuit issue?

- Yes, it is recommended to reset the OBDII code B3949 using an OBDII scanner after repairing the right front turn signal circuit problem. This will clear the error code and allow you to monitor if the issue has been successfully resolved.