I have seen a few of these with faulty handbrake systems where they have suffered rotten/corroded wiring.You will need to follow the wiring from the handbrake motor,located behind the right rear wheel,where it runs along the back of boot ledge and disappears under the floor where it exits under passenger seat and into passenger floor area below plastic false floor.Just in front of the passenger seat,below the carpet is a small relay and fuse box and a large multi pin connector block.Check this for any water damage.hth