AutoCodes – Buick – B3187 Buick

B3187 Buick Code - Left Rear Window Down Switch Circuit Low

Quick Answer

This Diagnostic Trouble Code (DTC) is generated by a passenger door window switch or a passenger door window switch circuit. Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window 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: B3187 Buick indicates Left Rear Window Down Switch Circuit Low.
Common causes: Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window 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 453

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 Mar 04, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3187 Buick Description

This Diagnostic Trouble Code (DTC) is generated by a passenger door window switch or a passenger door window switch circuit. Each passenger door window switch is mounted to the trim panel of the appropriate passenger door. The circuits and contacts of each passenger door window switch receive battery voltage and ground from the corresponding door module, i.e. Front Passenger Door Module (PDM), Left Rear Door Module (LRDM), or Right Rear Door Module (RRDM). When a passenger door window switch is operated, the switch contacts close and the associated door module interprets the flow of voltage as a specific request to move the window up or down. If conditions are correct for window operation to occur, the door module then powers the associated window motor and circuits to move the window.

OBDII Code B3187 Buick - Left Rear Window Down Switch Circuit Low - AutoCodes.com — B3187 Buick Code - Left Rear Window Down Switch Circuit Low

What does this mean?

What are the Possible Causes of the DTC B3187 Buick?

Faulty Left Rear Window Switch
Left Rear Window Switch harness is open or shorted
Left Rear Window Switch circuit poor electrical connection
Faulty Left Rear Door Module (LRDM)

How to Fix the DTC B3187 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 B3187 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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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 B3187 Buick Code

1. What does the OBDII code B3187 mean on a Buick?

B3187 indicates a problem with the Left Rear Window Down Switch Circuit, specifically that the circuit voltage is too low.

2. What are the common symptoms of code B3187 in a Buick?

Symptoms may include the left rear window not responding to switch commands, erratic window operation, or no movement at all.

3. What causes the B3187 code to appear?

Common causes include a faulty window switch, damaged wiring, a poor ground connection, or a malfunctioning window motor.

4. How can I diagnose the B3187 code on my Buick?

Start by inspecting the left rear window switch and its wiring for damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuit.

5. Can I still drive my Buick with the B3187 code active?

Yes, you can drive the vehicle, but the left rear window may not function properly until the issue is resolved.

6. How do I fix the B3187 code on a Buick?

Repairs may involve replacing the left rear window switch, repairing damaged wiring, or addressing a faulty window motor.

7. Could a blown fuse cause the B3187 code?

Yes, a blown fuse in the window circuit could result in low voltage, triggering the B3187 code.

8. How much does it cost to repair the B3187 code on a Buick?

The cost depends on the specific issue, but repairing or replacing a window switch typically ranges from $50 to $150, excluding labor.

9. Can a dead battery cause the B3187 code?

A dead or weak battery is unlikely to cause this specific code, but it can contribute to overall electrical issues if the system is not receiving proper voltage.

10. Do I need to reprogram anything after fixing the B3187 code?

In most cases, no reprogramming is needed. However, you may need to clear the code with an OBDII scanner once repairs are complete.