My 88 (7/87) XJS speedometer works for the first 3 miles each day-the cruise and trip computer work for the same distance. I have had the car on a hoist but can't find the speed sensor on the rear end. I used a scope and looked around the entire pumpkin. Does anyone have a picture of it, or a good description of where it is?

 

If you don't find a speedo *sensor* mountd in the cover of the differential......

Look on the left side of the transmission, towards the rear, for the speedo *transducer*.

The change to the diff mounted speedo sensor was at VIN 142xxx or 144xxx or something like that .....sometime during 1987 calendar year.

Another clue. If your differential cover is stamped steel, you'll have the transmission mounted speedo transducer. Models with the diff mounted sensor had a cast aluminum differential cover

Cheers
DD

 

If you have the diff speed sensor there is a module in the boot mine is on the LHS this is a pulse to converter