Rover part.Remove glove box cover and behind on top of plastic box section is a rectangular cover held in with screws connected to, I think if my memory is correct, a wiring connector. Disconnect wiring then remove screws and lift out. You will find 3 offset coiled wires (resistors) one or more of these will be burnt out or corroded. Replace with new unit and your problem should be solved
alan
July 2005