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Standard Ignition LS421 Back Up Light Switch
| Brand | Standard Ignition LS421 |
|---|---|
| Mounting Hardware Included | No |
| Activation Style | Switch |
| Color/Finish | Black, chrome |
| Connector Gender | Female |
| Connector Quantity | 1 |
| Connector Shape | Rectangle, square |
| Finish | Metal, plastic |
| Indicator Markings Included | No |
| Material | Metal, plastic |
| Mounting Bracket(s) Included | No |
| Mounting Type | Screw-in |
| Terminal Gender | Male |
| Terminal Quantity | 2 |
| Terminal Type | Blade |
| Wiring Harness Included | No |
| Fits | Ford · 6 vehicles |
Screw-in design. Installs with a simple threaded mount for a secure fit.
Metal and plastic construction. Balances durability with a lightweight, practical build.
Blade terminals. Uses a two-terminal connection for straightforward wiring.
Cross-references FR3Z15520A, NS16730 and S19361 for the same application. See all 3.
Will it fit your vehicle?
Free return shipping if it doesn't fit.
Standard Ignition LS421 Back Up Light Switch
Standard Ignition LS421 is a screw-in back up light switch built with a metal and plastic housing, black and chrome finish, and a female connector with two male blade terminals. It is a direct-fit electrical switch for restoring reverse lamp operation on select Ford applications, including the 2015-2020 Ford Mustang.
Key Features
- Back up light switch for reverse lamp circuit control
- Screw-in mounting type for a secure threaded installation
- Female connector with 2 male blade terminals
- Black and chrome color/finish with metal and plastic construction
- Standard Ignition LS421 replacement for select Ford Mustang models
- Cross-references OE-style part numbers FR3Z15520A and NS16730 for the same application
Detailed Description
The Standard Ignition LS421 back up light switch is designed for vehicles that use a threaded switch to signal reverse gear and activate the backup lamps. It features a rectangular/square connector shape, one connector interface, and a metal/plastic body for service replacement use. For buyers searching for a 2015-2020 Ford Mustang back up light switch or a Ford Mustang reverse light switch replacement, LS421 provides the correct electrical and mounting style for the listed application. The Standard Ignition LS421 is also referenced by part numbers FR3Z15520A and NS16730.
What It Helps Fix
- Reverse lights that do not illuminate when the transmission is placed in reverse
- Intermittent backup lamp operation caused by a worn switch
- Faults in the reverse light circuit related to switch contact wear
- Incorrect reverse lamp signaling after switch failure
- Service replacement needs on a 2015-2020 Ford Mustang
Installation Notes and Tips
Install LS421 in the threaded switch location specified for the vehicle and connect the existing female harness plug to the two blade terminals. Mounting hardware, a mounting bracket, indicator markings, and a wiring harness are not included. Verify connector shape, terminal style, and thread-in fitment before installation on your Ford Mustang reverse light switch replacement job.
Quality Assurance
Standard Ignition manufactures electrical service parts for vehicle repair applications, and LS421 is built to match the listed connector, terminal, and mounting configuration for the confirmed fitment range.
| Year | Make | Model | Transmission | Liters | Cylinders | Position | Notes |
|---|---|---|---|---|---|---|---|
| 2020 | Ford | Mustang | Manual | 5.2L | V8 | N/A | — |
| 2019 | Ford | Mustang | Manual | 5.2L | V8 | N/A | — |
| 2018 | Ford | Mustang | Manual | 5.2L | V8 | N/A | — |
| 2017 | Ford | Mustang | Manual | 5.2L | V8 | N/A | — |
| 2016 | Ford | Mustang | Manual | 5.2L | V8 | N/A | — |
| 2015 | Ford | Mustang | Manual | 5.2L | V8 | N/A | — |
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