The power supplies to fans N140, N141 and N142 are controlled by relay T23 and protected by fuse F57, both housed in the optional underfacia junction unit B101. Activation is controlled by a key housed in control unit M070. The control unit, from pin 5, supplies relay T23, which closes its internal contact to supply the fans.Control unit M070 comes with its own internal lighting that is activated by turning on the side lights. The heater controls also come with internal lighting G045 that is activated with the side lights on.