B3889 - Trailer Brake Lamps

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3    What is this?
Table of contents

B3889 Possible Causes

  • Faulty Trailer Brake Lamps
  • Trailer Brake Lamps harness is open or shorted
  • Trailer Brake Lamps circuit poor electrical connection
  • Faulty Trailer Lighting Control Module

How do I fix code B3889

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

Tech Notes

B3889 02 Trailer Brake Lamps Circuit Short to Ground
B3889 04 Trailer Brake Lamps Circuit Open

Cost of diagnosing the B3889 code

Labor: 1.0

The cost of diagnosing the B3889 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

B3889 Description

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The Body Control Module (BCM) provides a low reference signal and a 5 V reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM applies battery voltage to the center high mounted stop lamp control circuit and Trailer Lighting Control Module. The Trailer Lighting Control Module responds by applying battery voltage to the trailer stop lamp control circuit illuminating the trailer stop lamps.
OBDII Code B3889 - Trailer Brake Lamps - AutoCodes.com

B3889 More Information

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