The Jaguar XJ6 sedan offers its occupants a wide range of features and accessories, including power seats. As in all cars, though, the Jaguar's power seats are only a convenience until they stop working. Diagnosing and repairing completely inoperative XJ6 seats requires only a few common tools and can bring the luxury back to a luxury vehicle.
Open the vehicle's trunk. Lift the right hand portion of the trunk floor to access the vehicle's battery. Use the 10mm wrench to loosen the negative battery terminal, and disconnect the terminal from the battery. Lay the negative battery cable and terminal aside so that it cannot touch the negative post of the battery. Leave the battery disconnected for 15 minutes, and then re-connect the battery. Make sure the battery terminal is firmly tightened to the battery post, and re-install the trunk floor panel. Close the trunk, and check to see if the seat is still inoperative. The process of disconnecting the vehicle battery and re-connecting it is called a hard reset, and is often the only thing needed to fix XJ6 computer malfunctions. If your seat still does not function, proceed to the next step.
Locate the heelboard fuse boxes at the base of the back seat lower cushion. These fuse boxes are behind the carpeted panels below the front edge of the rear seat. Use the flat-bladed screwdriver to turn the round fastener in the middle of the carpeted panel. Turn the fastener 1/4 turn in either direction to release the panel, and pull the entire carpeted panel forward to reveal the fuse box. Set the panel aside, and remove the panel for the other fuse box the same way.
Connect the negative lead of your Volt-Ohm meter to any available ground point on the vehicle. The vehicle's body is connected to battery ground, so any clean connection to the body will work. Turn the vehicle's ignition on, but do not start the engine. Check for battery voltage at fuses F3, F4, F9, and F12 in the right hand heelboard fuse box, and F6 in the left hand heelboard fuse box. Use the positive lead of your meter to test for power at both exposed terminal points on each fuse. If any fuse lacks power on either of its terminals, pull the fuse out of the fuse box and look at the conductor inside the fuse's inspection window to see if it is intact. If any fuse's internal conductor is burned, replace the fuse with a fuse of the same current rating. If you replace a fuse in this step, check if the power seat functions properly after the fuse replacement.
If the seat still does not function, use the T40 Torx socket and socket wrench to remove the 4 bolts holding the driver's seat to the floor. The bolts are located at the ends of the two black metal seat rails underneath the seat. Tilt the entire seat assembly back to gain access to the underside of the seat. Locate the seat control module underneath the driver's seat. Identify the two blue connectors on the seat control module. One connector has 22 wire locations, and the other has 12 wire locations. On the connector with 22 locations, find the white and pink wire in the 11th wire location.
With the ignition on, use your meter to test for power at the wire. If there is no power at the wire, test for continuity between the white and pink wire and fuse F12 in the right hand heelboard fuse box. If there is no continuity, there is a break in the wire between the fuse box and the seat that must be repaired. Turn the ignition off. Check for power on the 12-location connector at wires 4, 6, 7, and 12. Wire 4 is colored brown and green, wire 6 is brown and light green, wire 7 is brown and orange, and wire 12 is brown and gray.
If any of these wires does not have power, check for broken conductors between the control module and fuse box. Use your meter to check for continuity from wires 4 and 6 to right-hand heelboard fuses F3 and F4, respectively. Use the meter to check for continuity from wires 7 and 12 to left-hand heelboard fuses F6 and F9, respectively. If any of these wires does not have continuity, there is a break in the wire that must be repaired.
If all fuses are intact and power is present at all the wires tested in the previous step, replace the seat control module and use the T40 Torx bolts to re-install the seat. Control module failure is common, but testing the wiring before replacing the module can avoid replacing a module unnecessarily.
