Xantia Speedo

DaveW · Post by **DaveW** » 20 Feb 2006, 18:39

I have a dead electronic speedo on my Xantia TD.

Can anyone suggest a test procedure ?
So far the only thing I know for certain is that the connector to the sensor at the diff. is clean - no oxidation - but chasing the wiring is awkward.

Can anyone point me to a link to a decent wiring diagram as the ones in the Haynes don't seem to cover this.

Dave.

davehughes · Post by **davehughes** » 20 Feb 2006, 20:37

I haven't experienced this with Citroens yet, but I used to be a BMW mechanic and the diff sensors used to be prone to failing on all models across the range. Try one from a scrapyard as a cheap process of elimination to start with before messing with the wiring. If it isn't that it might well be the instrument display, but it's easier to change a diff sensor than bugger around with the instrument display

DaveW · Post by **DaveW** » 20 Feb 2006, 23:32

Thanks for the reply.

I was hoping that someone would not say that!
The nearest scrappie likely to have a car or two is quite a jaunt away (I live in the sticks, N. Wales)

Is the sensor 'potted' in it's housing or just clipped in ? and is it just a Hall effect device?
I have a couple of 12v. Hall effect devices from other equipment so may be able to effect a repair if I can just locate the next connector and check to see if the sensor is outputting pulses.

I have read elsewhere that a problem can occur with the "speedo interface box" that allegedly lives behind the glove box ?????
Anyone heard of this beastie ?

There must be a full wiring diagram somewhere -

Dave.

AndersDK · Post by **AndersDK** » 21 Feb 2006, 00:10

I would think it is the old style Hall effect generator : a small pickup coil.
By far the cheapest and simplest device as its not polarised.

It would have 3 wires : 2 for the coil, 1 for a cablescreen.

And yes it simply gives a pulse output.

dnsey · Post by **dnsey** » 21 Feb 2006, 08:11

Since you appear to have some electronics knowledge - why not inject a square wave into the sensor input, and see it the speedo works then? Saves a lot of crawling round, and makes for a positive diagnosis.