Genuine Mazda Wiring Harness for later NA for when adding a hardtop with heated rear window.
This harness plugs into the harness on your MX-5 and completes the circuit to the hardtop defroster.
This harness is required if you are converting an NB8A or NB8B hardtop so the heated rear window work on an NA model.
This is the type with the larger 3-pin plug, some later mk1 cars may have a different connector so please check if you're not sure. Early cars (1989-91) do not have the wiring in the car for this.