Loss of all instruments.

[tattonpark6]

1996 X300 Executive. Have lost ALL my instruments and warning lights, that's 6 instruments and 22 warning lights, with the rest of the car working perfectly. Have checked the fuse list, and 2 are mentioned under 'instrument pack', a 5amp and a 10amp in the left side passenger seat area, which on inspection are looking good. Where do I go next, I can drive the car but I have no idea of speed, petrol quantity, oil pressure, water temperature, I will have to cancel the Xmas trip. Any tips, before I make a trip to Jaguar, [who will be closed anyway] will be very welcome. Ron. York City.

[RichardSEL]

This has got to be an earth return fault if you can find +12 in the instrument cluster somewhere -- all going out including the dial lighting at the same time is not an individual component/s fault.

So find an earth return (I've not had to do this on any of the three XJ8s I've had) and put a crock clip with a long wire attached to battery earth at the other end. That will bring the earth return back to whichever earthy side of the bulb that should be on that you've connected the crock clip to.

Because you've bought the earth return back, other bulbs may start lighting too. You'll then have to find where your proper earth connection's broken. Could be at the dash connector. But please note I've never had to do this on any of mine. You may need a circuit

As a quick simple check try twisting the dash board lights' dimmer to see whether the dial lights come to life?

Check that those two fuses you've found have clean spades and give a squirt of Servisol into their holders for good measure. You say you've "inspected" them. What does this mean? Have you put them across a meter set to continuity? Or have you swapped them for others?

[tattonpark6]

Thanks for all that RichardSEL, reference the fuses I have only done a visual check, and as you point out I need to make another more in depth check. I have searched the Forums and a chap in Holland has had the same, and his started with the Airbag warning light, bottom right on the panel, then as per mine all instruments to zero [6 off].
It seems a little pushing and pulling, connect and dis- connect of electrical cables has cured his, but he indicates it keeps on returning.
I will have to make a trip to Jaguar I think, but they are only open for 4 hours Monday morning and then Thursday for a full day, the base electrician will probably plug his meters in and give me the bad/good news in very short time.
Thank you again, I will keep you informed.
Regards. Ron. York City.

[naki]

Has any work been done on the car recently? Welding for example?
It’s worth reseating the plugs and checking for any broken or damaged pins on the plugs too.
Sometimes just moving the wires around can help pin point the weakness.

[tattonpark6]

Hello Naki,
no work done at all, reference welding or disturbing anything, but I am making some progress. Calling Jaguar was a waste of good time, especially with this holiday break, so I went into more Forums. Every example of total loss of instruments were started by the airbag red warning light coming on, and so having checked the two instrument pack fuses I decided to look next for airbag fuses. Two are shown in the fuse box charts, but the one in the right hand heelboard has a notice not to pull, 'it powers the deployment power energy reserve side of the air bag system', whatever that may amount too, sounds like a military instruction.
Back to the remaining, listed airbag fuse, and it is shown wired to the instrument panel on the drawing, F16 5amp in the boot fuse box, and on visual, it was blown, [progress at last], so replaced and turned the key, 22 warning lights all lit, started the engine, RPM, oil, water, fuel and battery condition, but the airbag light is still on.
So I will now go behind the glove box, and, as you say Naki, will move things about, especially the 'diagnostic box', which is a blue unit hidden down the back according to drawing, and I'll see what I achieve, making sure I disconnect the battery of course. Thanks for help. Take care. Ron. York City.

[RichardSEL]

<snip>
Back to the remaining, listed airbag fuse, and it is shown wired to the instrument panel on the drawing, F16 5amp in the boot fuse box, and on visual, it was blown, [progress at last], so replaced and turned the key, 22 warning lights all lit, started the engine, RPM, oil, water, fuel and battery condition, but the airbag light is still on.

Strewth, you report that the forums also have this fault reported with these symptoms. What a disaster of a design Who the 'eck drew up this circuit?

making sure I disconnect the battery of course.

Yes, some airbag systems deploy when a system "keep alive" voltage is removed
If both system supply volts are removed at the same time, as in battery disconnect, then no deploy occurs

[tattonpark6]

Everthing back to normal, having spent some weeks with the passenger airbag and the ECU disconnected.
Went to a number of garages with Jaguar signs proudly displayed but not one could diagnose a problem with the airbag system, 'not on a 1996 model, we can interrogate but nothing showing for the airbag' [lots of lines of problems for the engine which is running superbly well!!!].
Waited for a X300 to appear at the scrap yard, which was this week, and today went and removed burr walnut/passenger airbag/ECU, in that order, plugged ECU in and all was well, all lights on, then engine start, and all out
So to sum up, if you have a total loss of instruments on a X300, and a X380 maybe, start looking at the airbag electrical circuit, a 5 amp fuse in the boot, taking 22 lights and 6 instruments out of the loop, a Friday afternoon job from design office.
The question was asked reference why it could not be an instrument problem, and as mentioned before, my first check was 2 fuses listed for the instrument pack, and they were good, and so I had to start to look elsewhere.
Thanks to all for your help, and particularly Jaguar forums throughout the country, they gave me the initial lead to the airbag system, otherwise it would have been a long drag going over the complete car and all the various permutations.
Take care. Ron.C.H. York City.