B3889
Trailer Brake Lamps
B3889 is an OBD-II diagnostic trouble code meaning: Trailer Brake Lamps. Common causes: burnt out trailer brake light bulb, open or short circuit in wiring harness. Estimated repair cost: $11–56.
Symptoms
- Trailer brake lights do not work
- Dashboard warning
- Disconnecting Power to the Trailer Brake Light Circuit
Causes
- Burnt out trailer brake light bulb
- Open or short circuit in wiring harness
- Corrosion of trailer connector contacts
- Trailer control module malfunction
- Incorrect trailer connection
How to Fix
- Check trailer brake light bulbs for functionality
- Inspect the wiring harness and connectors for damage and corrosion.
- Check continuity with a multimeter
- Scan the control unit for additional errors
- If necessary, replace faulty components
Related codes
Error B3889 by Vehicle Brand
FAQ
What does the B3889 code mean?
B3889 is an OBD-II diagnostic trouble code that indicates: Trailer Brake Lamps
What causes a B3889 error code?
The most common causes of B3889 include: Burnt out trailer brake light bulb; Open or short circuit in wiring harness; Corrosion of trailer connector contacts; Trailer control module malfunction.
How do I fix a B3889 diagnostic trouble code?
To fix B3889: Check trailer brake light bulbs for functionality. Inspect the wiring harness and connectors for damage and corrosion.. Check continuity with a multimeter. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with B3889?
Do not drive — repair immediately
How much does it cost to fix B3889?
The estimated repair cost for B3889 is $11–56. Actual cost depends on your vehicle, location, and labor rates.
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