on a 1998 r reg 106 its situated just above the fuse box. open the glove box and on the left is a flap of material. lift that and you will see the fuses. above the fuses are the relays. for this model its the orange coloured relay. to get at the relay its easier to remove the glovebox. to do this look under the bottom edge of the glovebox lid and you will see two white plastic pegs (the hinges) slide them out using a flat bladed screwdriver and the glove box comes away. older models not sure cause i'm working on sons car.
steve
October 2009