This is a regular verb. It follows the conjugation pattern of the verb hablar.
PresentPresente
El ascensor no funciona desde el lunes.
The elevator hasn't been working since Monday.
ImperfectPretérito imperfecto
La radio vieja todavía funcionaba bien.
The old radio still worked well.
FutureFuturo
Con esta pila, el reloj funcionará otra vez.
With this battery, the clock will work again.