Electronic Speedo senders

[rknowles74]

Hi all,

I have a Smiths electronic speedo in my Nostalgia XK120 with a dedicated sender that senses the bolts on the prop shaft. I want to remove this sender as I think it could be causing some erratic readings on the speedo, and instead use the original sender from the donor XJS that is mounted into the differential.

In theory this should be quite simple, however the smiths gauge can cope with two type of sender, and I dont know what type the jaguar is.
It appears the two types are known as PNP, or NPN. One of then needs the gauge connected between the sender and ground, and the other needs the gauge connected between the sender and +ve 12v.

Does anyone know the rightway of connecting up the original sender unit - especially since in the XJS the sender was connected to a speed interface unit that is not used in the XK120.

Thanks,
Richard

[NATONEIL]

I cannot help you with this one Richard I have a mechanical drive speedo. Might I suggest that you also post your question tot he XJS section of the board, if you have not already done so