X300 – Electrical

11 – Electrical ( )


11.1 – Fuses and Relays ( )

Fuses are contained in 5 main fuse boxes as listed below. The descriptions are from the Jaguar handbook and aren’t always the clearest. When diagnosing a problem, bear in mind that several fuses may be involve in getting a particular component to function ( eg power feed, control relay feed, electronic control module feed ), so do check the full list.

Engine Bay Left
F1 25 Heated Front Screen
– Right Side
F2 10 Main beam headlamp
– Left side
F3 25 Starter Solenoid
F4 10 Dip beam headlamp
– Left side
F5 10 Side light, indicator
and repeater – Left side
F6 20 Windscreen wiper
F7 Unused
F8 15 Air conditioning
water pump
F9 Unused
F10 10 Horn 1
F11 30 Engine Cooling fans
– series & parallel modes
F12 Unused
F13 Unused
F14 10 Horn 2
F15 25 Heated Front Screen
– Left Side
F16 Unused
F17 30 Engine Cooling fans
– series mode
F18 10 Front Fog lamp –
Left side
Engine Bay Right
F1 Unused
F2 10 Main beam headlamp
– Right side
F3 Unused
F4 10 Dip beam headlamp
– Right side
F5 10 Side light, indicator
and repeater – Right side
F6 5 Engine ECU
F7 25 Air pump ( 6 cyl
) Ignition coils ( 12 cyl )
F8 10 Air con clutch (
note separate inline fuse )
F9 Unused
F10 5 Alternator, Lighting
control module – Right side, Air con clutch, windscreen &
headlamp wash heaters
F11 20 Engine ECU relay
supply, injectors
F12 10 Engine ECU, Starter
Relay, ignition coil sensing and air pump ( 6 cyl ), injection
relay and ECU sensors ( 12 cyl )
F13 10 Windscreen washer
F14 10 Oxy sensor heaters,
idle speed control valve
F15 Unused
F16 10 Air pump control,
Vacuum valve ( 12 cyl ), intercooler water pump ( 6 cyl supercharged
F17 30 Headlamp power wash
F18 10 Front fog lamp –
Right side
Rear Seat Heelboard
– Left Side
F1 Unused
F2 10 Heated Door Mirrors,
Instrument Illumination
F3 15 Seat motors –
Right side
F4 15 Seat motors –
Right side
F5 10 Instruments
F6 5 Seat ECM, low power
door switches, mirror motors
F7 30 ABS pump
F8 Unused
F9 20 Cigar lighters
F10 5 Cruise control
F11 20 Heater blower –
left side
F12 5 Instruments
F13 15 Steering Column
F14 10 Auto transmission
ignition switched supply
F15 30 Window motors –
left side
F16 5 ABS ignition switched
F17 Unused
F18 10 Air Con supply
Rear Seat Heelboard
– Right Side
F1 15 Central Locking
F2 5 Gearshift interlock,
Centre console switches, interior lighting switch
F3 15 Seat motors –
left side
F4 15 Seat motors –
left side
F5 5 Auto transmission
F6 Unused
F7 30 ABS Control
F8 10 Interior lights,
boot lights
F9 25 Seat heaters
F10 5 Diagnostic system,
Fuel pump relay coil
F11 20 Heater blower –
Right side
F12 10 Air con, Seat ECM,
Mirror heater relay, Power steering
F13 Unused
F14 10 Mirrors, heater
rear window, cigar lighter, rear lighting control
F15 30 Windows – Right
F16 10 Windscreen wipers,
Front screen heater control, Front lighting control – left
side, water pump relay, headlamp levelling, clock
F17 15 Airbag
F18 15 Sunroof
Battery Compartment
F1 25 Stereo
F2 5 Tail and plate lights
– left side
F3 15 Reverse lights,
stop and indicator light – left side
F4 10 Security system
F5 10 Main CPU
F6 5 Diagnostic system,
F7 30 Fuel pump
F8 15 Boot release, aerial,
stereo unswitched feed
F9 15 Rear fog lights,
stop and indicator light – right side
F10 5 Stereo control relay
F11 25 Towing module
F12 5 Phone and accessory
F13 10 Accessories
F14 Unused
F15 25 Heated rear window
F16 5 Airbag warning
F17 Unused
F18 5 Tail and plate light
– right side


11.10 – Sound System ( )


11.10.1 – Radio Wiring ( )

The purple/orange wire in the radio wiring harness will mute the radio when grounded. It can be directly connected to the yellow wire of a Nokia car kit for automatic mute when the phone is in use.


11.10.2 – Radio Aerial/Antenna Replacement ( )

These seem to be a commonly failing item. The wiring connector was changed during the lifetime of the car, so ensure you get the right one when replacing.

When replacing, lift it slightly up at the bottom and then slide it down over the window button.


11.10.3 – Radio Aerial/Antenna Maintenance ( )

Periodically wipe the raised antenna with a damp cloth in an upward direction, which avoids pushing dirt into the mechanism. Switch-cleaner is preferable to WD40 as a cleaning agent, as it does not leave a sticky residue behind.

The standard radio unit will periodically display a message requesting that the aerial mast or cassette unit be cleaned. This is a useful reminder, but more frequent cleaning, particularly in dirty road and weather conditions, may be advisable.


11.10.4 – Radio Connections, CD Player and Cartridge Removal ( )

The standard radio has an 8 pin DIN style socket for attaching the CD stacker, which is wired through into the boot. Where no factory CD player is fitted, the Alpine CHM620 can be fitted using the existing wiring and will be controlled from the standard head unit.

The stereo also has a 5 pin DIN socket for connecting a separate power amplifier, available in some markets to drive a sub-woofer.

In addition, there is the main 20 pin connector to the stereo, with pins 1 – 10 on top going right to left and pins 11 – 20 on the bottom. 1 and 10 are 12V feeds, 4 switches the lighting on and off and 3 is a variable feed from the lighting dimmer circuit.

If the CD cartridge appears to be stuck, try pushing a credit card or similar under the cartridge to the right of the eject button.


11.11 – LCD Clock ( )

Clock modules occasionally suffer from faint displays, caused by bad contacts between a circuit board and flexible ribbon cable inside the unit. It is possible to make a repair, though some may consider it to be a less than professional fix!

Access can be gained following the instructions in section 10.1. Remove the connector at the rear of the clock unit itself, undo the four screws attaching it to the rest of the assembly and then take it to a bench area for further work.

The unit itself is opened by undoing the small screws at the rear and releasing the plastic tabs. Whilst the unit is open, take care not to lose any of the small components in there. Release the LCD panel itself by carefully spreading the black tabs holding it into the white plastic bracket. The panel is attached to the main circuit board by a ribbon cable, and it is the connection at the circuit board end that is the problem.

Tape the ribbon cable in place and use a business card or piece of pizza box ( both have been successfully deployed! ) to put pressure on the ribbon cable where it connects to the pcb, behind the white plastic bracket.

Take the unit to the car in plug it in. Use the time set buttons to cycle through all the digits to make sure the fix is complete before reassembly. If segments are still missing or faint, additional pressure may be needed on the ribbon cable.

When all is working, reassemble the clock unit and then refit into the centre console. Attach the cable and take care not to stress any other wires as you fit the console back into position.


11.12 – Memory Seats and Steering Wheel ( )

Some models are fitted with the memory seat, steering wheel and mirrors functionality. The ECU’s associate the position of the various devices with a particular key fob and adjust them accordingly.

The motors, particularly for the steering wheel, are known to fail and replacement has been the only solution reported. In some cases, the system appears to become inactive, which can be overcome by disconnecting the battery for an hour or so.


11.13 – External Temperature Sensors ( )

These are located in the brake cooling ducts, behind the front bumper and in front of the wheelarch liner. Access can be obtained by removing the front undertray.

The left hand sensor is used as input to the climate control system. The right hand sensor is used to control the washer reservoir heater and washer jet heaters, active below 4C, and to control the heated seats, active below 26C.


11.14 – High Level Brakelight ( )

Where fitted, this is driven from the relay located in the red, right hand socket in the boot fuse box. The relay is identical to the two others adjacent.


11.15 – Front Indicator Bulb Replacement ( )

The manual indicates a special tool is required to remove the indicator unit from the front bumper. The tool is flat plastic blade, and can therefore be improvised yourself. You can use metal if you are careful to protect the finish on the bumper.

The blade slots into a gap on the inboard side of the indicator unit and releases an internal catch by pushing it to the outboard side of the car.

Bulb replacement and refitting the unit and then straightforward.


11.16 – Sports / Normal Switch Light Replacement ( )

Jaguar does not offer a replacement bulb, but insists you replace the switch. However, replacement is straightforward with a sub-miniature bulb as sold in electronics shops.

To gain access to the switch, remove the ashtray and plastic transmission selector surround (see section 10.1 of this guide).

Using a small screwdriver, release the clear plastic lugs holding the lower part of the switch into the black upper casing and remove the lower part of the switch. The bulb sits inside a small piece of rubber which itself sits on two metal prongs which carry the current to the bulb. The wires from the bulb go back up through the rubber in the same holes as the mounting prongs.

Remove the blue cap from the bulb then pull the rubber mount off the prongs. Gently pull the bulb wires through to the lower side of the rubber, straighten them, then lift the bulb out of the rubber from the top.

To refit, put the new bulb in, making sure the wires go through the two tiny holes in the rubber mount underneath the bulb. Bend the wire round and up inside the mounting holes, then push the rubber back down onto the prongs. Make sure the switch position is the same on upper and lower halves of the switch, then click the lower assembly into the upper casing.

Reattached the wiring and refit the plastic transmission surround and ashtray.


11.2 – Headlight Removal ( )

The headlights are mounted on three ball joints and can be removed by pulling the whole unit firmly. They are sealed beam units and must therefore be replaced as an entire unit should the glass be broken


11.3 – Climate Control Test and Diagnosis ( )

The climate control system is significantly different from earlier XJ40 models in that all flaps and valves are electrically operated, with no reliance on engine vacuum. The system is of the ‘constant air flow’ type, meaning that fan speed is adjusted based on road speed to maintain the desired flow rate.

The system can be put through a self-test procedure as follows:

Warm the engine then switch off. Press both ‘Auto’ and ‘Recirc’ buttons and hold whilst restarting the engine.

All the panel LED’s and LCD display will flash. Any areas failing to flash suggest a problem with the bulb, display or function in that area.

Press ‘Auto’. If the display is zero, then no error codes are stored. Any other number is an error code. Use ‘demist’ to cycle through up to five stored codes. Press ‘demist’ and ‘heated rear window’ to clear a displayed code. Code 23 indicates low refrigerant pressure.

Press ‘Recirc’ to enter diagnostic mode. Repeatedly pressing ‘Face’ will step through the 8 different combinations of vent actuation and you will be able to hear and feel vents and fan operating.

Pressing ‘Off’ will restore the unit to normal operation with the default settings.

List of control codes:

0 – Normal Operation – No fault codes present, wait 30 seconds for system
11 – Motorized In-car Aspirator (sensor element)Open / short circuit. Panel
fault codes are not stored for blown aspirator failure of motor.
12 – Ambient Temperature SensorOpen / short circuits.
13 – Evaporator Temperature SensorOpen / short circuits.
14 – Engine Coolant Temperature InputInstrument pack output.
15 – Heater Matrix Temperature SensorOpen / short circuits.
21 – Solar SensorOpen / short circuits.
22 – Compressor Lock SignalOpen / short circuits. Low gas charge, low
compressor oil, loose belt.
23 – Refrigerant Pressure SwitchOpen / short circuits. Low gas charge*.
24 – Differential PotentiometerOpen / short circuits.
31 – LH Fresh / Recirc. PotentiometerOpen / short circuit in pot.
feed. In certain circumstances, the motor can over-travel and log further
faults. Cycling the ignition two or three times can cure this.
32 – RH Fresh / Recirc. Potentiometer
33 – Cool Air Bypass Potentiometer
34 – Defrost Potentiometer
35 – Centre Vent Potentiometer
36 – Foot Potentiometer
41 – LH Fresh / Recirc. MotorCheck for short / open circuits in motor drive
lines. Motor flap sticking / jammed.
42 – RH Fresh / Recirc. Motor
43 – Cool Air Bypass Motor
44 – Defrost Motor
45 – Centre Vent Motor
46 – Foot Motor

Other symptoms that don’t generate codes

No heat – Airlock in system. Water pump inoperative. Water valve stuck
closed. Faulty engine coolant thermostat.
One vent failing to open or close – Broken linkage.
Poor airflow – Blower motors – incorrect operation (eg fuses blown).


11.5 – Windscreen Washer Pump and Jets ( )

The pump is located on the side of the washer fluid reservoir, in the wheel arch on the right side of the car.

To access, remove the wheel and pull out the clips at the front and upper sides of the plastic wheel arch cover. You can now pull the cover aside sufficiently to access the pump.

Unplug the pump and pull it from the tank, noting that any washer fluid will pour out.

A stuck pump can sometimes be repaired by removing the sealed top, lubricating the internals and then resealing using glue and/or melting the plastics together.

The jets are held in place with a central screw. Loosen the screw to allow the sprayer to be lifted upwards and the water and electrical connections removed.


11.6 – Remote Key Fob Programming ( )

Open the boot lid and drivers door, and switch on the ignition. Rock the valet switch, in the centre console, 5 times. The system will chirp to indicate it has entered learning mode.

On models with seat/mirror/steering wheel memory functions, the first remote will be linked to memory 1, second to memory 2 etc.

Press the larger, lock, button of the remote. The system will chirp to confirm it has got the signal. If it doesn’t receive any signals for 15 seconds, it will chirp twice and exit learn mode.

To programme further remotes, rock the valet switch once. The system will chirp twice for remote number two, three times for number three etc, then press the lock button of the remote as above.

When finish, wait 15 seconds for the system to time out and chirp twice, turn off the ignition, close the doors and boot lid and the job is done!


11.7 – Dim-Dip Mirror ( )

These seem to be a commonly failing item. The wiring connector was changed during the lifetime of the car, so ensure you get the right one when replacing.

When replacing, lift it slightly up at the bottom and then slide it down over the window button.