you might be able to 'tap' the pulse in the wiring loom to check it is the sensor..
The pulse should be available as colours CB & (HM/)HR on pins 2 & 5 on Connector 149A (the big one, behind the battery)
in positions 2 & 5, on this connector, you should have Orange/White (CB) & (Grey/Brown/) becoming Grey/Red.
The colour change on pin 5, has Grey/Red on the 'engine' side of the wiring, and Grey/Brown on the dashboard side.
the negative reference for the speedo sensor should be an N (black) at position 14, on the same connector.
If you are clever; it might be possible to run some wiring from one of the first pair (pins 2 or 5), and the negative reference (pin 14), into the cabin, and feed a multimeter on AC volts, to see if you can see anything 'pulsing' during a slow roll across a carpark.
(I think i'd try this with the multimeter leaning against the windscreen from the outside, at SLOW speeds)
However, three factors may prevent a result-
*whether the speedo generates a decent pulse below 10mph
*the sample frequency of your multimeter
*and whether the relationship between the speedo and sender are compromised, and the speedo itself is dragging the pulse from the sender down.
But; I'd certainly try this first before attempting the sender swapout.
Edited by dante giacosa (04/06/2018 09:51)