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1157 BAY15D P21/5W Dual-Color Switchback LED Bulb (54-SMD, Wireless DC 12V-24V)

The MIDCARS 1157-54L35 is a wireless BAY15D/1157/P21/5W switchback dual-color LED bulb with open-frame 6063 aluminum body and 54x SMD 2835 LEDs. It delivers 300 LM 6500K Pure White DRL and 400 LM Amber turn signals across DC 12-24V, using the factory dual-contact socket for direct power separation - no external ACC wire required.
Product Model:1157-54L35
Socket / Base:BAY15D Dual-Contact Bayonet Base (1157 / P21/5W) - Pin 1 (Low): White DRL 5W circuit, Pin 2 (High): Amber Turn 21W circuit, Shell: Common Ground. Wireless 1:1 direct replacement, no external ACC wire required. Not interchangeable with PY21W / BAU15S (offset-pin single-filament) sockets.
Operating Voltage:DC 12-24V (Wide Voltage, Transient Protection up to 36V)
Rated Power:White DRL: 3.0W | Amber LED: ~4W
Luminous Flux:300 LM (DRL White) / 400 LM (Signal Amber)
Color Temperature:White: 6500K | Turn Signal Amber: 595-600nm Automotive Amber
LED Emitter:54x SMD 2835 LEDs
Body / Enclosure:Open-Frame Solid 6063 Aluminum Heat-Sink Body (Direct Thermal Dissipation)
Color Options:White + Amber (Standard), Warm White + Amber, Red + Amber, Dual Amber
Wiring & Logic: 100% Wireless plug-and-play dual-contact socket - Pin 1 (Low) feeds White DRL, Pin 2 (High) feeds Amber turn signal, shell is common ground. Switchback logic: DRL White ON → Turn Amber flashes (White OFF) → Signal OFF (White restores after 1.0s delay)
Quality & Warranty:CE (EMC Compliant), RoHS | 2 Years Factory Warranty
  • Product Details

Product Overview: 1157 BAY15D Dual-Color Switchback LED Bulb (Wireless 1:1 OEM Direct Replacement)

The MIDCARS 1157-54L35 is an engineered dual-color switchback LED bulb designed for seamless 1:1 direct replacement of conventional dual-filament incandescent bulbs including 1157, BAY15D, P21/5W, 2057, 2357, and 7528. Tailored specifically for front park/turn signal fixtures and motorcycle lighting systems, this model features a completely wireless architecture (No external ACC lead required), utilizing the vehicle's original dual-contact socket for direct power separation between low-wattage White DRL and high-intensity Amber turn signals.

Constructed with a heavy-duty Solid 6063 Aluminum heat-sink body in an open-frame direct thermal dissipation design (No glass or plastic outer cover), it eliminates trapped heat, ensuring superior natural convection and rock-solid junction temperature control across wide DC 12V - 24V operating systems (with transient surge protection up to 36V). Driven at conservative, high-efficiency currents across 54 SMD 2835 emitters, it guarantees over 30,000 hours of continuous operating lifespan supported by our 2-year factory warranty.

Precision Dimensional Blueprint & BAY15D Socket Specifications

Detailed dimensional blueprint showing precise 1:1 bulb profile (D18mm x L49mm), 180° radial index pins with unequal height (High/Low alignment pins for physical mistake-proofing), and dual bottom contacts matching international P21/5W standards without headlight housing modification:

1157 BAY15D LED Bulb Dimensional Blueprint D18mm L49mm

Real Illumination & Dual-Color Light Pattern

High-definition live workshop demonstration showing crisp 6500K Pure White daytime running light and vibrant 595-600nm amber turn signal illumination under full 360-degree radial diffusion:

1157 BAY15D LED Bulb White DRL 6500K Illumination
1157 BAY15D LED Bulb Amber Turn Signal 595nm Illumination

Intelligent Switchback Operating Logic & Dual-Contact Architecture

How True Wireless Switchback Function Operates:

  • OEM Socket Direct Integration: The BAY15D base features two distinct bottom solder contacts matching the vehicle's dual-filament harness (Pin 1: 5W circuit for White DRL / Parking; Pin 2: 21W circuit for Amber Turn Signal; Base Shell: Common Ground).
  • Default Mode (Parking / DRL): When parking lights or DRL are activated, the low-power 5W circuit energizes the internal controller to illuminate 6500K Pure White continuously.
  • Turn Signal Active (Switchback Override): When the driver signals a turn or hazard, the high-power 21W circuit receives flasher power. The intelligent onboard micro-controller instantly overrides and shuts off White DRL, flashing 595–600nm Automotive Amber exclusively for maximum traffic visibility.
  • Turn Signal Cancelled: Once the turn signal is turned off, the internal controller waits 1.0 second to confirm signaling has ended, then automatically restores the 6500K Pure White DRL smoothly without flicker.
⚠ Important Compatibility & Anti-Hyper Flash Notes:

1. Hyper-Flash Notice (Flasher Relay Operation): Because LED bulbs draw significantly less current than original 21W incandescent filaments (4W vs 21W), vehicles equipped with thermal or mechanical flasher relays may detect the low load and hyper-flash (fast blink). To restore factory-standard flash rates:

  • For 12V Systems: Add an external 25W 10 Ohm gold aluminum load resistor (or replace with an electronic LED flasher relay).
  • For 24V Systems (Trucks/Heavy Duty): Add an external 25W 27 Ohm load resistor (do NOT use 10 Ohm on 24V systems, as it will dissipate over 57W and overheat).
  • Installation Note: The load resistor must be wired exclusively across the Turn Signal (21W) circuit and ground. Never connect a load resistor to the continuously-lit DRL (5W) circuit!

2. Bulb-Out Warning / CANBus Systems: Modern European vehicles with active bulb-monitoring computers may display a dashboard warning. Dedicated CANBus-equipped versions or external plug-and-play decoders are available upon request for B2B fleet orders.

Primary Commercial & Automotive Applications

1. Front Turn Signal & DRL Conversion

Upgrades clear or amber front turn signal housings on passenger cars, pickup trucks, and SUVs into dual-function 6500K Pure White Daytime Running Lights and high-contrast Amber turn signals without modifying OEM wiring.

2. Motorcycle Dual-Filament Retrofit

Widely adopted in cruiser, touring, and street motorcycles with front dual-filament 1157 bullet or flat-lens turn signals, providing continuous white running safety illumination combined with unmistakable amber directional flashing.

3. Tail / Brake & Rear Turn Customization

In custom vehicle and trailer applications, the Red + Amber dual-color option enables red running/brake illumination switching to amber rear turn signals in a single standard 1157 light cluster.

4. 24V Commercial Vehicle & Fleet Lighting

Rugged wide-voltage driver accommodates 24V bus, coach, commercial truck, and trailer electrical systems, delivering durable solid-state vibration resistance and extended maintenance cycles.

B2B Wholesale, OEM Manufacturing & Customization Capabilities

As an integrated automotive LED design and manufacturing facility established in 2016 in Dongguan, China, MIDCARS offers comprehensive OEM and ODM support for global distributors, wholesalers, and private brands:

  • Precision Laser Engraving: Custom logo, part number, batch coding, and voltage specifications permanently laser-marked on the 6063 aluminum lamp collar.
  • Custom Packaging Solutions: Retail color boxes, customized blister card hanging packs, dual-pack anti-static pouches, and bulk master packaging with customer brand artwork.
  • Electrical & Voltage Engineering: Dedicated 6V-12V configurations for classic vintage automobiles and retro motorcycles, or optimized 24V commercial truck driver designs.
  • Rapid Sampling & Production Lead Times: Standard warehouse samples dispatched within 2–3 business days; custom branded prototypes completed in 5–7 business days.
  • Warranty & Compliance: Backed by our standard 2-year factory replacement warranty, fully compliant with CE (EMC Directive) and RoHS environmental standards.

Contact our factory sales team directly at sales02@zhishanled.com for wholesale tier pricing, distributor agreements, and technical engineering specifications.

Frequently Asked Questions

What sockets does the 1157-54L35 fit?
It directly replaces 1157 / BAY15D / P21/5W dual-filament bulbs (cross-refs 2057 / 2357 / 7528), fitting front park/turn signal fixtures on cars, trucks, and motorcycles.
Does this bulb need an external ACC wire for switchback?
No. It uses the factory dual-contact socket - Pin 1 (low) feeds the White DRL, Pin 2 (high) feeds the Amber turn signal, with the shell as common ground. 100% wireless plug-and-play.
What is the operating voltage?
DC 12-24V wide voltage with transient surge protection up to 36V, covering 12V car/motorcycle and 24V commercial systems.
What should I do if the turn signal hyper-flashes?
Add an external load resistor across the amber turn circuit (12V: 25W 10Ω; 24V: 25W 27Ω), or upgrade to an electronic LED flasher relay.