Xantia Instruments dead

[alantech]

Hi,
This is my first post on this site.
I have a Xantia 1.9 TDI Desire R rege (Jan '98), The other day when I started it up the only activity on the instrument panel was the battery light. Speedo, Tacho and gauges were not working, the Stop and Preheat lights did not come on when ign turned on. The indicator and beam lights all work.
I've checked the fuses, all ok. Stripped the ignition switch, cleaned and reassembled it (never seen a switch that uses the cables as contacts before). I took out the instrument cluster, without removing steering wheel, it's the one with 4 contact blocks black, red, green and blue, there are no faults on the circuit board that I can find.
Any ideas?

[addo]

It does sound like a positive feed is not there! On a facelift car, the feeder fuse for clocks and "K" light is F12.

[alantech]

I've checked the fuses and also checked with meter that the feed is reaching the board.

[addo]

Even odder! You may have a dead short due to a collapsed diode on the display circuit board.

[CitroJim]

It's not a facelift S2 if it has four connectors. S2 instruments have just two connectors.

It's odd. Does the car run OK?

[alantech]

The supply has disappeared now, all of the other fuses fed from the same line from ign are powered, but f12 is dead both ends. How do I get the fuse box out to check the fuse sockets?

[CitroJim]

Alan,

I'll dig you out some wiring and harness (loom) diagrams for your car but it will be hard as the diagrams that show the instruments are many.

F12 may be a red herring and may only apply to an S2 car. Yours is an S1 car...

To help me (and others) get this on the right track, can you tell us any parts of the electrical system that appear to have failed, besides the instruments?

To know precisely what does and doesn't work will be a great help in narrowing this problem down...

[alantech]

Ok, it is a failure on F12, I did a quick temporary bridge from F2 feed side to f12 feed side and everything has come back on.
I've dropped the fuse box but there's not enough slack in the loom to pull it down far enough to see or do anything. I might just make the bridge a bit more robust for now unless anyone can suggest a reason not to.
As to the S1/S2 thing, the electrics on my car seem to be a mixture of the two wiring systems. Any previous faults have been cured following the S2 circuits in the manual, everything seemede to match up with them and not the S2 circuits until I took the instruments cluster off. According to the 'log book' it's a 1.9 TD Desire 2, registered in Jan 98. There's an SX on the back if that means anything.

[CitroJim]

That's good, a nice piece of proof there

I's best not try to get at the topside of the fusebox, the only way to do so is to remove the dash!

I suspect the fault may be in the usual place - in the infamous '10AV' loom that runs across the very front of the car under the radiator. It gets wet and inside the loom there's a few splices. They get dam and corrode and go open-circuit...

Here's a set of diagrams showing F12 and it's associated looms...

Schematic Diagram

Harness Diagram

Locations Diagram

Hope that helps...

[alantech]

Thanks Jim,
I'm sure that diags will prove useful, I'll go ahead with the alteration and let you know how it goes.
As to what version my car is, I'm a bit mystified. It has body colour bumpers and trims and spoiler on the boot, according to Haynes that's a facelift model. Also most of the elecs seem to conform to the later circuit diagrams, the aircon cirtainly does.
Thanks for your help, this is a great site, look forward to visiting regularly (hopefully not just for faults).
Regards,
Alan