Which Filament in Optronics Bulb # A1157B is Used for the Turn Signal
Updated 09/09/2013 | Published 09/05/2013 >
Question:
Which filament on a 1157 bulb is used for the turn signal
asked by: Pat W
Expert Reply:
The Optronics 1157 Replacement Bulb, part # A1157B, and similar dual-filament bulbs have two different filaments. One filament is of a different resistance value, and thus makes a brighter light. That is why one bayonet on the bulb casing is at a different position than the other bayonet - so that you dont install the bulb the wrong way. The basic filament usually on the brown wire is running lights, the other filament usually green or yellow depending on which side of trailer has different resistance value, making it brighter, and used for braking/turn signal.

Product Page this Question was Asked From
Continue Researching
- Q&A: Is the Running Lamp or Brake/Turn Signal Filament in 1157 Bulb Supposed to Be Brighter
- Q&A: Do You Still Have To Clean and Repack Dexter E-Z Lube Axles Once a Year
- Q&A: How Wide are A-Frame Trailer Couplers CA5400 and CA5100B
- Q&A: What are the Measurements of Optronics Replacement Side Marker Lens # AL9RB
- Q&A: Replacements For Hadco Trailer Axle With Hadco 3109 Hubs
- Q&A: Does the Replacement Lid for Camco RV Polyethylene Propane Tank Covers Come In Black
- Q&A: Towing Capacity for 2019 Honda CR-V