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Can you add blind spot monitoring to a car after purchase?

Yes, you can generally add blind-spot monitoring after buying a car, through a dealer-approved retrofit or a reputable aftermarket kit, though availability, cost, and installation complexity vary by model.

What blind spot monitoring is and why it matters

Blind spot monitoring (BSM) uses sensors—radar or cameras—to detect vehicles in adjacent lanes and alert the driver with lights in the side mirrors or audible warnings. It helps reduce lane-change collisions and is increasingly common on new cars. For older vehicles, retrofitting BSM can improve safety, but results depend on how well the system integrates with the car’s existing safety features.

Can you add it after purchase?

OEM dealership retrofit vs aftermarket kits

There are two main routes to add BSM after purchase. Costs and install requirements vary: dealer-installed, factory-approved retrofits tend to be the most seamless but can be pricier, while reputable aftermarket kits offer lower upfront costs but require careful compatibility checks and professional installation.

OEM dealer retrofit: Factory-approved option installed by a dealer or certified shop, designed to integrate with the car’s safety suite. Availability depends on the model and year.

Aftermarket systems: Independent kits (camera- or radar-based) that can be installed by a shop. Quality and integration vary; some work with existing mirrors or displays, others may require additional dash or wiring work.

Calibration and integration: Regardless of path, the system must be calibrated to the vehicle’s geometry and electronics. In some cases, software updates or VIN programming are necessary for proper operation.

In short, adding BSM after purchase is typically possible through either OEM retrofits or aftermarket solutions, but the right option depends on your car, budget, and tolerance for potential fitment and calibration work.

Key factors to evaluate before installation

Before committing to a retrofit, consider these factors to avoid wasted money or safety gaps.

Vehicle compatibility: Not every model or year supports retrofitting BSM, especially if the car’s safety architecture isn’t designed to accept a retrofit module.

Sensor type and placement: Radar-based and camera-based systems require correct sensor placement; improper positioning can cause false alerts or missed detections in rain or snow.

Calibration and testing: The system should be calibrated and tested after installation, ideally with a diagnostic scan and real-world driving checks.

Warranty and insurance: Check whether retrofits affect the vehicle’s warranty or insurance premiums, and whether the installer offers warranties on parts and labor.

Cost versus benefit: OEM retrofits usually offer deeper integration but higher cost; aftermarket kits can be cheaper but may offer limited compatibility with other safety features.

Clarify whether the system will display alerts on the side mirrors, instrument cluster, or a central display, and whether you can customize alerts or temporarily disable the feature for certain driving conditions.

What to expect during installation

Installers typically mount sensors on the rear corners or bumper, route wiring to a control module, and calibrate the system to your vehicle. The process can take several hours and may require software updates or diagnostic programming. Afterward, request documentation of all changes for your records and warranty considerations.

Summary

Adding blind-spot monitoring after purchase is feasible in many cases, though not universal. A dealer-installed retrofit usually offers the most seamless integration with your car’s safety systems, but it can be costly. A reputable aftermarket kit can be a more affordable alternative if it’s compatible with your model and installed by a qualified technician. Always verify compatibility, calibration requirements, warranty implications, and the installer’s credentials before proceeding.

How much does it cost to add blind spot monitoring to a car?

Adding blind spot detection can cost anywhere from $75 to over $1,000, depending on whether you choose a DIY kit or a professional installation, and the quality of the system. Simple aftermarket kits can be as low as $75, but professional installation will likely add another $200 or more to the total.

Cost breakdown

Parts: The cost of aftermarket kits ranges from about $75 to over $500 for higher-end systems.
Professional installation: This can add $200 to $500 or more, depending on the complexity of the vehicle and the system. The total price for a professionally installed system typically ranges from $450 to $1,000.
Factory-installed systems: These are generally more expensive and often included as part of a package with other options.

Factors that influence the price

System technology: Kits with more advanced features, like radar sensors and rear cross-traffic alerts, will be more expensive than basic systems.
Quality and reliability: Higher-priced systems tend to offer better accuracy and fewer false alarms.
Vehicle complexity: The cost of installation can vary based on the vehicle, as it requires specific expertise and can be time-consuming.

Can you add blind spot monitoring to a car that doesn't have it?

The answer is yes, in most cases you can add blind spot monitoring to your car.

Can you add a blind spot monitor aftermarket?

Yes, you can add blind spot monitoring (BSM) aftermarket to almost any vehicle, with systems typically costing between $250$ 250$250 and $500$ 500$500 for the kit itself, plus installation. These kits use either radar sensors or cameras to detect vehicles in your blind spots, and can be installed professionally or as a DIY project if you have the necessary skills. The system will then alert you with a visual cue, such as a light on your mirror, and/or an audible warning.
You can watch this video to see a review of a cheap blind spot monitoring system: 1mShortWithTechYouTube · Apr 12, 2025
Types of aftermarket BSM systems

Sensor-based: These systems use ultrasonic or radar sensors, typically mounted on the rear of the car, to detect other vehicles.
Camera-based: These systems use small cameras to monitor your blind spots. The feed is then displayed on your dashboard or integrated into your rearview mirror.

Installation options

Professional installation: A professional installer can determine the best system for your vehicle and ensure it is installed correctly. The total cost, including parts and labor, typically ranges from $450$ 450$450 to $1,000$ 1 comma 000$1,000.
DIY installation: For those with some mechanical skills, it's possible to install a system yourself.
- License plate systems: are often the simplest to install as a DIY project.
- Bumper-mounted sensors: are more complex and require removing the bumper cover.
- The most time-consuming part of any installation is running the wiring through the car's cabin and trunk.

This video demonstrates how to install a blind spot monitoring system using a DIY kit: 54sInfotainmentYouTube · Jul 31, 2023
What to expect

Alerts: Systems alert you with an LED light in your side mirror or a beep from inside the car when a vehicle is detected in your blind spot.
Sensitivity: Some systems allow you to adjust the sensitivity.
Integration: Kits are available that can be integrated into your existing mirrors, though this can be more complex and requires finding compatible mirror lenses.
Advanced features: More advanced systems may include additional features like ADAS (Advanced Driver-Assistance Systems) that monitor the vehicle in front of you and can even detect pedestrians.

What to consider

Cost: The cost varies depending on the type of system and whether you include professional installation. Expect to pay between $250$ 250$250 and $500$ 500$500 for the kit itself.
Complexity: If you are not comfortable with basic automotive wiring and installation, a professional installation is recommended to avoid damage to your vehicle or improper system function.
Vehicle: Many aftermarket systems are designed to be universal, but it is important to confirm compatibility with your specific vehicle before purchasing.

Can I add features to my car after purchase?

A variety of add-ons aftermarket modifications can be made to your car, but it's important to think through how they can affect the vehicle's resale value. In most cases, these are not things most buyers want, which means they decrease the value of your car.

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.