B1803
Low Severity (Level 1)Lamp Turn Signal Rear Output Circuit Open
B1803 usually means lamp Turn Signal Rear Output Circuit Open.
Can you still drive with B1803?
✅Safe to drive — this is an informational or minor issue. Schedule diagnosis at your convenience.
Typical repair cost: $10 – $200
Severity Level 1 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Turn signals working intermittently, then stopping completely
- Turn signals not working — no response when activated
- Infinite resistance in the turn signal/hazard circuit — broken wire or disconnected connector
- Fault may be intermittent — code may clear itself and reappear
- Reduced vehicle functionality related to the turn signal/hazard system
Possible Causes
- Broken wire or connector pin in the turn signal/hazard system harness — common at flex points like door jambs or where wiring moves
- Disconnected or loose electrical connector — may have been bumped during other repairs
- Failed turn signal flasher — internal open circuit from age, heat cycling, or vibration
- Corrosion completely severing a wire or connector terminal — green crust on copper wiring
- Wiring harness damage from rodent chewing — look for nesting material near the engine or under dash
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($4-113 at shop, free at auto parts store for basic scan)
- Visually inspect the turn signal/hazard system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $82 diagnostic fee at shop)
- Trace the turn signal/hazard system wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($84-213 labor for diagnosis and repair)
- Check and reseat all connectors in the turn signal/hazard system circuit — disconnect, inspect pins, clean with electrical contact cleaner, apply dielectric grease, and reconnect firmly ($11 DIY or $73 shop minimum)
- If turn signal flasher has failed internally (open circuit inside), replace it — don't try to repair sealed components ($10-200)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does B1803 mean?
B1803 stands for "Lamp Turn Signal Rear Output Circuit Open". B1803 usually means lamp Turn Signal Rear Output Circuit Open.
Can you drive with B1803?
Safe to drive — this is an informational or minor issue. Schedule diagnosis at your convenience.
How much does it cost to fix B1803?
Repair costs for B1803 typically range from $10 to $200, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($4-113 at shop, free at auto parts store for basic scan); Visually inspect the turn signal/hazard system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $82 diagnostic fee at shop); Trace the turn signal/hazard system wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($84-213 labor for diagnosis and repair).
Will B1803 clear itself?
Explore Repair Costs
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