View Full Version : Jaguar XJ6 Speedometer

18-10-01, 06:39 PM
I am hoping to use Jaguar XJ6 Mk3 instruments. Does any body know what is going on inside the gearbox tranducer for the electronic speedo drive.

It has to be connected to the correct polarity for it to work. I have not been able to produce an output voltage or measure any pulses. However when connected as it should be with a positive supply to transducer and speedo it works ok.

What I would like to do is construct a separate transducer perhaps from a sensor on the prop shaft or something similar. Has anyone attempted this I wonder?

18-10-01, 10:20 PM
I didn't use Jag instruments but I have a sensor on the propshaft. It is a fast reedswitch which pulses when it passes over the magnets which you stick on the prop. I had initial problems when I had 4 magnets on the prop. The speedo would suddenly jump and become erratic at speed. I took one of the magnets off and evenly spaced the remaining 3 and it now works fine. I suspect that the reedswitch contact was bouncing when it was asked to do too much.


19-10-01, 01:43 PM
You maybe able to change the reed switch for a Hall-effect switch (dead cheap from RS/Farnell etc), switching speed is far higher so it'll work much better and be much more reliable as there are no mechanical parts.