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A 1991 4l xjs, manual, the speedometer and mileometer have stopped working, apparently the fault is a sensor that comes from the rear differential up to the boot of the car and then connects to something that goes to the dashboard.
What is the sensor called? And any idea where I could get one. I could easily fit it if I could find one, someone at my local club said it's called a transducer, but i can't find it under that name.... HELP

rsims193141,

I would suggest not changing anything until you've pinned down where the problem lies.

There are 3 key elements in the chain:

- The speed sensor, which is mounted in the rear diff. (Earlier cars had a transducer mounted on the side of the transmission)
- The interface module, which is located in the boot
- The speedo itself

The problem could lie in any of the 3.

One way to help pin down if the problem lies in the diff sensor is whether the trip computer(if you have one fitted) is reading distance. If so, the diff sensor is working (& also possibly the interface module).

The interface module uses two output wires - one for the speedo and one for the trip computer

The instrument cluster is also prone to problems, both from the printed circuit wiring strip deteriorating, and also from poor earth connections.

And lastly the speedo itself could have failed.

Hope that gives you some ideas.

Paul

Just in case it helps, here are what I *think* are the part nos for the bits which Paul refers to above. They are VIN number dependent in some cases, expensive if you can find them and no longer available new from Jaguar, but may be available second hand.

Sensor DBC 2632
Interface unit DAC 11375
Speedo DAC 6465

Illustrations are available on the Jaguar Classic parts website:
https://parts.jaguarlandroverclassic.co ... 0Nzc0Mjc3/

Ahh, brilliant information, thanks, the trip and mileometer are not working, so it does look like the sensor, now i know what I'm looking for it might be easier to find. Thank you

rsims193141,

You may be right, but my gut feel is that it will be the interface module or somewhere in the wiring to it, or from it to the front of the car. IMLE, the diff sensors are really not prone to failing. Maybe start by checking the signal to the interface module.

Cheers

Paul