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As the title says, the speedo went intermittent, then more off than on. When on, it's correct. The Tach reads okay, and the trip computer distance advances. VIN is 158578. It has the speed sensor on the back plate of the differential.
I thought I would first reseat the connectors, but where is the transducer interface unit mounted? The wire from the transducer goes up through the trunk behind the spare, and then reenters the body cavity.
If you follow that Wire in the Boot/Trunk where it goes into the Cavity, then you will find the little Black Speedo Interface Box although its well hidden away and you may have to move the ECU or even unbolt that metal plate to get to it
Having said that your problem with the 'Speedo' is far more likely to do with some corrosion on the Pins of the 'Multi Plugs' that plug into the back of the 'Speedo Binacle' here is how to remove the 'Speedo Binnacle' in order to clean them (which also fixed my intermittent 'Speedo' with the same problem as yours)
Thank you SO MUCH for the tip to clean the connectors on the back of the instrument panel. I suspected connectors when it first started getting intermittent, but I didn't know how to get to them, and was reluctant to poke around without some expert guidance. So the link to the other thread with the photos was perfect. And as you can see in the photo: problem solved!!! I also learned a new word—binnacle.
Don't thank me thank the GF aka 'Clever Clogs!' as apparently my small contribution was of limited use!
Anyway glad you got it fixed, nothing more frustrating than a dodgy Speedo and 'Binnacle' crept into the mix from when I used to have a boat which cost me far more to run than any amount of XJS's and nowhere near as much fun!
89 XJS No Speedo but Tach and Dist Seem Okay
