The 2021 Mazda CX-30 has 10 electrical switch & relay parts with verified fitment on this page — 5 part types and 6 brands, covering all 3 engine options (2.0L L4, 2.5L L4 and 2.5L L4 Turbocharged). Each part includes a manufacturer part number and application notes.
On the 2021 Mazda CX-30, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches. Most of the listed parts are Brake Light Switch (6 parts), A/C Refrigerant Pressure Switch (1 part) and Accessory Power Relay (1 part). The other 2 part types cover the remaining 2 parts.
The 2021 Mazda CX-30 was sold with 3 engines. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
6 brands supply electrical switch & relay parts for the 2021 Mazda CX-30, led by STANDARD MOTOR PRODUCTS (4 parts), WELLS (2 parts) and UAC (1 part), plus 3 more brands. Quality grades include Economy and Standard Replacement.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 2021 Mazda CX-30. 2 parts have it, including STANDARD MOTOR PRODUCTS SLS355T (Brake Light Switch) and STANDARD MOTOR PRODUCTS SLS355 (Brake Light Switch). Each part number opens a page with every vehicle that part fits.
A/C Refrigerant Pressure Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| UAC Fits: 2.0L L4 | SW11649C | 🇨🇦 CA | Pressure Transducer | View on Amazon |
This table covers the pressure switches on the A/C circuit. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
One part is listed for the 2021 Mazda CX-30 — UAC SW11649C.
Accessory Power Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 2.0L L4 | RY2031 | 🇨🇦 CA | In Engine Compartment | View on Amazon |
This table covers the relays that control the Accessory Power circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
This group shows a single part: STANDARD MOTOR PRODUCTS RY2031.
Brake Light Switch
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Popular Fits: 2.0L L4 | SLS355T | 🇨🇦 CA | T-SeriesColor/Finish: Blue, Gray | View on Amazon |
| AUTOTECNICA Fits: 2.0L L4 | MA1319181 | 🇨🇦 CA | View on Amazon | |
| DORMAN Fits: 2.0L L4 | 920493 | 🇨🇦 CA | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Popular Fits: 2.0L L4 | SLS355 | 🇨🇦 CA | Color/Finish: Black, Blue | View on Amazon |
| ROSTRA Fits: 2.0L L4 | 620296 | 🇨🇦 CA | View on Amazon | |
| WELLS Fits: 2.0L L4 | 1S8007 | 🇨🇦 CA | View on Amazon |
This table covers the pedal-mounted switch that turns on the brake lamps. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
6 Brake Light Switch parts are listed for the 2021 Mazda CX-30, from STANDARD MOTOR PRODUCTS, AUTOTECNICA, DORMAN and 2 other brands. STANDARD MOTOR PRODUCTS SLS355T carries the "Popular" badge.
In the Economy grade, STANDARD MOTOR PRODUCTS, AUTOTECNICA and DORMAN supply 3 parts: the catalog's value-priced group. A representative part number is STANDARD MOTOR PRODUCTS SLS355T.
The Standard Replacement section lists 3 options from STANDARD MOTOR PRODUCTS, ROSTRA and WELLS — built to original-equipment specification. STANDARD MOTOR PRODUCTS SLS355 is listed in this group.
Listed part numbers: STANDARD MOTOR PRODUCTS SLS355T, AUTOTECNICA MA1319181 and DORMAN 920493, plus the other parts above.
Defroster Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 2.0L L4 | RY2031 | 🇨🇦 CA | View on Amazon |
This table covers the relays that control the Defroster circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
One part is listed for the 2021 Mazda CX-30 — STANDARD MOTOR PRODUCTS RY2031.
Horn Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS Fits: 2.0L L4 | 1R2324 | 🇨🇦 CA | View on Amazon |
This table covers the relays that control the Horn circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
This group shows a single part: WELLS 1R2324.
Buying Electrical Switch & Relay Parts for a 2021 Mazda CX-30
On this vehicle, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches.
- Match the engine first. Every electrical switch & relay part here is engine-specific; each row shows which engine(s) it fits.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Brake Light Switch and A/C Refrigerant Pressure Switch .
Frequently Asked Questions
How many electrical switch & relay parts fit the 2021 Mazda CX-30?
Our catalog currently lists 10 electrical switch & relay parts for the 2021 Mazda CX-30 across 5 subcategories and 6 brands, covering all 3 engine options (2.0L L4, 2.5L L4 and 2.5L L4 Turbocharged). Each part is matched to the engine(s) it fits.
Do electrical switch & relay parts differ between 2021 Mazda CX-30 engines?
Yes. Every electrical switch & relay part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of electrical switch & relay problems on a 2021 Mazda CX-30?
Common symptoms include accessories that work intermittently, a click without action, or one function dead while its fuse tests fine. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Mazda CX-30 was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 Mazda CX-30?
First match the engine — each row shows which engine(s) the part fits. Then swap a suspect relay with an identical known-good one from the fuse box before buying — it is the fastest diagnostic there is. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Mazda CX-30
Electrical Switch & Relay Parts for Other Mazda CX-30 Years
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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.