Hello fellow Jag enthusiasts


A fortnight ago I drove 15 miles in my 1991 V12 XJS to my "local" swimming pool. It was seven in the morning so I didn't use windows. After the swim I got back in the car, started up the engine and then tried the driver side window - no response.
Tried the passenger side - no response. On the journey back I noticed this clicking sound - sounded more like "tonking" coming from under the glove box. I arrived home and after some research realized this was the thermal cut-out fuse. The noise occurs as soon as the ignition is switched on and starts immediately and occurs every 5 seconds or so ( whether you operate window switches or not) . The cigar lighter and mirrors all work but the windows are dead.

I took off both window switches from the ski slope and then turned the ignition on - no "tonking noise". Mmmm - fitted two new switches - "tonking" starts again. Fitted a new passenger side switch and tested with no driver side switch fitted - "tonking" starts,
Fitted a new driver side switch with no passenger side switch fitted - Bingo! The driver side windows worked and no "tonking noise".

Having narrowed it down to the passenger side I am not sure what to do next. The passenger switch is probably not the cause of the problem as I fitted a brand new one so the fault must lie downstream from the switch. Do I have to take off the passenger side door card? Has anyone had these symptoms before?

One possible clue to all this - I did take a left hand band faster than normal on that drive to the swimming pool - maybe that caused a wiring issue?

 

I’m not sure about the noise, but I’ve had intermittent responses from both of my window switches. The switch is the most likely culprit, they’re all crap. Take it apart and clean the contacts. They’re bare copper and oxidize fairly easily. Some fine sandpaper should have the switch back in business pretty quickly.

 

If the exact same switch you used successfully in the driver's side produces the fault in the passenger side, then it is a wiring fault. Nothing for it but to get the wiring diagram and do some continuity testing. I can post a diagram if you need it.

 

Do not sandpaper the contacts! That wears away the surface and whatever is there below oxidizes in days, so you'll be doing this weekly.