Dependant on model, the Defender is provided with either one or two interior lamps. One in the front, and one in the rear of the vehicle (if fitted). Both lamps can be switched on manually using their integral switches. If any door, including the tail door, are opened, the lamp(s) will illuminate. If an immobilisation system is fitted to the vehicle, the lamps are controlled by the Alarm ECU. The ECU contains a time out feature which switches off the interior lamps after eight minutes if any door is left open, thus preventing unnecessary battery drain.
Operation
Non-immobilisation (Defender 90 Hard Top only)
Feed from the positive battery terminal is connected to fusible link 2 (C632-1) of the engine compartment fuse box by a brown wire. Fusible link 2 (C907-2) is connected to fuse 2 (C580-3) of the passenger compartment fuse box by a brown wire.
Fuse 2 of the passenger compartment fuse box (C580-4) supplies a current to both the front (C317-3) and rear (C356-3) interior lamps on purple wires. Both lamps are connected in parallel. The front interior lamp has an integral switch. With this switch in the off (normal) position (C317-1) the lamp can only be earthed by the LH (C266-1) and RH (C265-1) door switches. Both switches are connected in parallel by purple/blue wires. With the front doors in the closed position both door switches are open, failing to provide a route to earth. Therefore the lamp does not illuminate. If either the LH or RH door is opened,
the circuit is completed and the front interior lamp will illuminate.
With the integral switch in the on position (C318-1) a direct route to earth is provided on a black wire, illuminating the lamp.
The rear interior lamp (C356-1) is connected to the tail door switch (C751-1) by a purple/blue wire. If the tail door is opened, the circuit is completed and the rear interior lamp will illuminate.
Immobilisation (Defender 90 & 110 Hard Top only)
Feed from the positive battery terminal is connected to fusible link 2 (C632-1) of the engine compartment fuse box by a brown wire. Current flows through fusible link 2 (C907-2) to fuse 2 (C580-3) of the passenger compartment fuse box on a brown wire.
Fuse 2 of the passenger compartment fuse box (C580-4) is connected to the front interior lamp (C317-2) by a purple wire. The interior lamp has an integral switch. With this switch in the off (normal) position (C317-1), a feed is sent to the alarm ECU (C061-1). The Alarm ECU is connected (C061-16) to the tail door switch (C751-1) and the LH door switch (C033-1), which are wired in parallel. Both are connected by purple/blue wires. With both of these doors closed, the door switches are open, and fail to provide a route to earth for the ECU. If either door is opened, the switch is closed, providing a route to earth
and illuminating the interior lamp.
The alarm ECU (C061-5) is also connected to the RH door switch (C054-1) on a slate/white wire. With the door closed, the door switch is open, and fails to provide a route to earth for the ECU. If the door is opened, the switch is closed, providing a route to earth and illuminating the interior lamp.
With the interior lamp switch in the on position (C318-1 a direct route to earth is provided on a black wire, illuminating the lamp.
The alarm ECU also receives a signal from the RF handset (see engine immobilisation). When the correct signal is received, the alarm ECU will illuminate the interior lamp. The lamp will remain illuminated until either the alarm is re-armed using the handset, the ignition is switched to position "II", or the time out period elapses.
Immobilisation (Defender 110 Truck Cab only)
Feed from the positive battery terminal is connected to fusible link 2 of the engine compartment fuse box (C632-1) by a brown wire. Fusible link 2 (C907-2) is connected to fuse 2 (C580-3) of the passenger compartment fuse box by a brown wire.
Fuse 2 of the passenger compartment fuse box (C580-4) supplies a current to the interior lamp (C357-3) on a purple wire. The interior lamp has an integral switch. With this switch in the off (normal) position (C357-1) the only earth path is via the alarm ECU (C061-1) on a purple/white wire.
The alarm ECU (C061-16) is connected to the LH door switch (C033-1) by a purple/blue wire. If the LH door is closed, the door switch is open, and fails to provide a route to earth for the ECU. If the door is opened, the switch is closed, providing a route to earth and illuminating the interior lamp. The alarm ECU (C061-5) is also connected to the RH door switch (C054-1), this time by a slate/white wire. The RH door switch operates in the same way as the LH door switch.
With the interior lamp integral switch in the on position (C563-1), a direct route to earth is provided on a black wire, illuminating the lamp.
The alarm ECU also receives a signal from the RF handset (see engine immobilisation). When the correct signal is received, the alarm ECU will illuminate the interior lamp. The lamp will remain illuminated until either the alarm is re-armed using the handset, the ignition is switched to position "II", or the time out period elapses.
Immobilisation (Defender 90 / 110 Station Wagon, & Crew Cab)
Feed from the positive battery terminal is connected to fusible link 2 (C632-1) of the engine compartment fuse box by a brown wire. Fusible link 2 (C907-2) is connected to fuse 2 (C580-3) of the passenger compartment fuse box by a brown wire. Fuse 2 of the passenger compartment fuse box (C580-4) supplies a current to the front interior lamp (C357-3) and the rear interior lamp (C925-3), which are connected in parallel. Both lamps are fed by purple wires.
The front interior lamp has an integral switch. With this switch in the off (normal) position (C357-1), the only earth path is via the alarm ECU (C061-1) on a purple/white wire.
The alarm ECU (C061-5) is connected to the RH front door switch (C054-1) by a slate/white wire. If the RH front door is closed, the door switch is open, and fails to provide a route to earth for the ECU. If the door is opened, the switch is closed, providing a route to earth and illuminating the interior lamp. The alarm ECU (C061-16) is also connected to the LH front door switch (C033-1 this time by a purple/blue wire. The LH front door switch operates in the same way as the RH door switch.
Connected in parallel with the LH front door switch is the tail door switch (C751-1), the RH rear door switch (C930-1), and the LH rear door switch (C930-1). All three switches are connected by purple/blue wires and work in the same way as the RH front door switch.
With the front interior lamp integral switch in the on position (C563-1 a direct route to earth is provided on a black wire, illuminating the lamp.
The rear interior lamp operates in the same way as the front interior lamp. When the integral switch is in the off (normal) position (C925-1), the only earth path is via the alarm ECU (C061-1) on a purple/white wire. The door switches are fed by the alarm ECU as before.
With the rear interior lamp integral switch in the on position (C563-1 a direct route to earth is provided on a black wire, illuminating the lamp.
The alarm ECU also receives a signal from the RF handset (see engine immobilisation). When the correct signal is received, the alarm ECU will illuminate the interior lamp. The lamp will remain illuminated until either the alarm is re-armed using the handset, the ignition is switched to position "II", or the time out period elapses.