B1685: Lamp Dome Input Circuit Failure
MediumBodyLighting
What does B1685 mean?
B1685 is a diagnostic trouble code indicating "Lamp Dome Input Circuit Failure". This code relates to your vehicle's lighting and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.
Symptoms you may notice
- Check engine light (MIL) illuminated on dashboard
- Intermittent warning lights
- Erratic gauge readings
Estimated repair cost
Typical range in Australia (parts + labour)
$100 – $500 AUD
Common causes
- Faulty lighting component
- Wiring or connector issue in the related circuit
- Failed sensor providing incorrect readings
- Software/calibration issue requiring ECU update
- Related component causing secondary fault
What should you do?
This code sits in the exterior lighting. Nothing about how the car drives changes, but how easily other road users see you does, and a light out is an on-the-spot fine and an inspection failure. Worth sorting before you next drive at night.
Get a diagnosis for YOUR car
Code B1685 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.