A vehicle selector, also called a parts finder, is the dropdown filter at the top of an auto parts store: the shopper picks their vehicle and the store shows only the car parts that fit it. Shopify does not include one. This guide explains what the dropdowns have to do, the three ways stores add them, and the steps with ClearFitment.

What "dependent dropdowns" means

The dropdowns are multi-level, and each level depends on the one before it. Pick a vehicle type, then only its brands show. Pick a brand, then only that brand's models show. Then engine, then year. A shopper never sees a combination the store has no parts for, which is the point: a flat list of every model, or a free-text search box, lets them choose a vehicle that leads to an empty page.

The levels are yours to choose. Common shapes:

Year, Make, Model. The standard in North America, usually written YMM.
Make, Model, Year. The same fields in the order many shoppers think in.
Vehicle type, Brand, Model, Engine. Common in Europe, where "brand" is the usual word for make and engine size decides which part fits.
Make, Model, Submodel, Engine, Year. For catalogues where trim or engine changes the answer.

What a selector needs behind it

Fitment data. A row for each product and each vehicle, or vehicle range, it fits. The selector's options come from this data, so a model with no parts never appears.
A place on the page. Usually the home page and the top of collection pages.
A results page. Where the shopper lands after choosing, listing the parts that fit.
Memory. The chosen vehicle should follow the shopper from page to page, so they pick once.
An answer on the product page. A shopper who arrives from Google lands on a product, not on the selector. They need to be told whether this part fits their vehicle.

Three ways to add one

Shopify's own filters

Shopify's Search & Discovery app can turn a metafield or a tag into a storefront filter. It is free and it is native. Filters are a different thing from a selector, though. They sit on a collection or search page, so the shopper has to be browsing a collection before they can narrow it, and there is no selector to put on the home page. The platform's filter limits also apply. For those limits, see Shopify's collection filter limit for auto parts.

Custom theme code

A developer can build the dropdowns in the theme and drive them from tags or a data file. You own the result and it can look exactly as you want. You also own the upkeep: each theme update, each new vehicle and each supplier file is your developer's work, and tag-based matching inherits the 250-tag limit described in Shopify's product tag limit and fitment.

A fitment app

An app stores the fitment, supplies the selector as a block you place in the theme editor, and serves the results. The differences between apps are in how they hold the data, how they bill, and what they change in your theme. They are compared in Shopify Year Make Model (YMM) search apps compared.

Setting it up with ClearFitment

Choose your fields. The app starts with Make, Model, Submodel, Engine and Year. You can rename a field (Make to Brand, for example), remove the ones you do not use, add your own such as Vehicle type, and set the order. The order of the fields is the order of the dropdowns.
Import your fitment data. Upload a CSV and match its columns to your fields. You see a preview of what will be added, changed and skipped before anything is written.
Place the vehicle search block. In the theme editor, add the vehicle search block wherever you want the selector. It is an app block, so it sits in your theme without changing it.
Add the product-page blocks. The fit badge tells the shopper whether the product fits the vehicle they chose. The fitment table lists the vehicles it fits.
Test it as a shopper. Pick a vehicle, check the results, open a product that fits and one that does not.

The shopper's vehicle is remembered as they move around the store. My Garage, synced to customer accounts across devices.

What to check before you choose

Your theme. App blocks need an Online Store 2.0 theme. Some older themes cannot take them at all, and on those the selector cannot be placed.
Your data. A selector is only as complete as the fitment behind it. If your data is in tags today, check whether any product sits at the tag limit before you move it.
What you need beyond a selector. ClearFitment has no VIN or registration-plate lookup. If your shoppers expect to type a plate, you need an app that offers it.