Hi all can someone advise me. have problem with 92 facelift XJS, it looks like the immobiliser has cut off the ignition and fuel pump, the light on the steering column is steady when in the car, but when key is turned to position 2 it flashes, have checked relays, inertia switch, changed alarm ecu, the key fob works, the three prong thingy you put into the steering column works, have tried locking all doors, had the centre consul off but cant find any switches or wires, can anyone help or have an alarm wiring diagram for a 92 model. bit of a loss to know what to do next, except get the matches!!!! thanks John f

 

The "three prong thingy" doesn't sound like that its a Jaguar alarm at all. The Jaguar alarm unit is behind the right rear light and plug into a big white connector next to the antenna.
The led light should be near a valet rocker switch also on the column. The horn for the alarm will be inside the front wing and will chirp when fob is pressed.

 

Hi Malc yes its a factory fitted alarm, yes I have found all the alarm components, on mine the led is on the left, ignition switch in middle then the valet switch, alarm chirping when pushed, any other ideas?