NA/NBSeller listing
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View listing at Mossmiata; opens in a new tabMiata · Buyer's guide
NA/NB Miata Radiator Fan Motors, Relays and Thermoswitch Diagnosis
1990-2005 NA/NB Miata. Fan control differs by year, engine, A/C and ECU strategy; 1990-1993 uses a dedicated thermoswitch path.
Current seller options
WHERE TO BUY
Open an exact listing, then confirm fitment, stock, price, and shipping with the seller before ordering.
Seller links checked . Prices and availability can change.
NA/NBSeller listing
Listed priceSee seller for current price
View listing at Mossmiata; opens in a new tabNA/NBSeller listing
Listed priceSee seller for current price
View listing at Treasure Coast Miata; opens in a new tabNA/NBSeller listing
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View listing at Mike's Miata Parts; opens in a new tabWhat you need to know
Confirm year, engine, A/C and main versus auxiliary fan. Test fuse, relay command, voltage/ground and motor current before replacement; do not condemn the radiator for a control fault.
OEM numbers
1990-1993 fan-switch path includes Moss 902-870 application. NB main fan assembly checked against BP4W-15-025Dorman 620-785. Mazda relay applications are year-specific.Supersession
No universal fan-control chain is asserted. Main and A/C auxiliary fans, relays, thermoswitch/ECU input and wiring are separate components.
Fitment
Confirm year, engine, A/C and main versus auxiliary fan. Test fuse, relay command, voltage/ground and motor current before replacement; do not condemn the radiator for a control fault.
Aftermarket options
New motor/assembly, relay, thermoswitch and shroud/fan kits exist. Performance dual-fan kits change scope and wiring and are not OEM supersessions.
Before you buy
Match main versus A/C fan, year and control strategy. Test fuse, relay, wiring, temperature input and the motor before buying; an overheating car may also have a separate cooling-system fault.
Research and fitment sources
Supersede reviewed 7 unique research sources for this guide. 4 also appear above as a seller or official action and are not repeated here; 3 additional citations follow.
Research last verified .