Illumination Relay

Illumination Relay

Vehicles fitted with an instrument dimmer switch are also fitted with an illumination relay. Fuse 14 of the passenger compartment fuse box (C0589) provides a constant battery feed to the illumination relay (C1976) on a pair of P wires. The earth path for the relay coil (C1976) is controlled by the CCU (C0592) on a BR wire.

The CCU provides an earth path for the relay coil when it receives a 'key in' signal from the transponder coil (C0049). The energised illumination relay (C1976) provides a feed to the automatic transmission selector (C0244) on an NR wire.

NOTE: If an instrument dimmer is not fitted, the feed to the automatic transmission selector (C0244) is provided by fuse 4 of the engine compartment fuse box.

For more information on instrument dimmer operation, refer to the Interior Illumination section of this manual.  INTERIOR ILLUMINATION.

Interior Lamp(s)

3 Door Fuse 14 of the passenger compartment fuse box (C0580) provides a constant battery feed to the interior lamp (C0357) on a P wire. When the interior lamp switch is in the normal (central) position, the earth path for the lamp (C0357) is controlled by the CCU (C0593) via the passenger compartment fuse box (C0580) on a PW wire. The CCU will illuminate the interior lamp if it senses any of the doors are open (see 'Central Control Unit – CCU').

When the switch is moved to the 'ON' position, current flows across the bulb to earth via the lamp fixings. This results in the lamp being illuminated irrespective of the condition of the door switches.

When the switch is moved to the 'OFF' position, the circuit is broken. This results in the lamp being extinguished irrespective of the condition of the door switches.