B3885 GMC Code - Trailer Left Tail Lamp Circuit
Quick Answer
The Trailer Lighting Control Module receives a serial data message from the Body Control Module (BCM) indicating that the vehicle park lamps have been activated. Common causes include Faulty Trailer Left Tail Lamp, Trailer Left Tail Lamp harness is open or shorted, Trailer Left Tail 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
- B3885 GMC indicates Trailer Left Tail Lamp Circuit.
- Common causes
- Common causes include Faulty Trailer Left Tail Lamp, Trailer Left Tail Lamp harness is open or shorted, Trailer Left Tail 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.
Code B3885 GMC Description
What are the Possible Causes of the DTC B3885 GMC?
- Faulty Trailer Left Tail Lamp
- Trailer Left Tail Lamp harness is open or shorted
- Trailer Left Tail Lamp circuit poor electrical connection
- Faulty Trailer Lighting Control Module
How to Fix the DTC B3885 GMC?
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.
Code Tech Notes
B3885 04 Trailer Left Tail Lamp Circuit Open
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B3885 GMC 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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Frequently Asked Questions about B3885 GMC Code
1. What does the OBDII code B3885 mean on a GMC?
B3885 indicates a fault in the trailer left tail lamp circuit, often involving an open or short circuit.
2. What are common symptoms of the B3885 code in a GMC?
Symptoms may include the trailer's left tail lamp not working, a warning light on the dashboard, or trailer lighting malfunction messages.
3. What causes the B3885 code to appear?
This code can be caused by damaged wiring, corroded connectors, a faulty bulb, or a malfunctioning trailer lighting control module.
4. How can I diagnose the B3885 code on my GMC?
Begin by inspecting the trailer left tail lamp wiring, connectors, and bulb for damage or corrosion. Use a multimeter to check for continuity and proper voltage.
5. Can a blown fuse trigger the B3885 code?
Yes, a blown fuse in the trailer lighting circuit can cause this code. Check the fuse box for any blown fuses related to trailer lights.
6. Is it safe to drive with the B3885 code active?
Yes, but it’s not recommended if you’re towing a trailer, as the left tail lamp will not function properly, reducing visibility and safety.
7. How do I fix the B3885 code on my GMC?
Repairs may involve replacing a faulty bulb, repairing damaged wires, cleaning corroded connectors, or replacing a faulty trailer lighting control module.
8. Can a trailer wiring harness issue cause the B3885 code?
Yes, a damaged or improperly connected trailer wiring harness can trigger this code. Inspect the harness for wear or disconnections.
9. Does the B3885 code always mean there’s a problem with the trailer itself?
No, the issue could also be within the vehicle’s trailer wiring system or control module, not just the trailer.
10. Do I need professional help to resolve the B3885 code?
Not necessarily. If you’re comfortable with basic electrical diagnostics, you can often resolve the issue yourself. Otherwise, consult a professional mechanic.
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