Not sure what a satnav would need a very inaccurate speed signal for
What would you do if it was a 924 with a cable rather than electrical speedo

I don’t believe there is any way to “tap” into the speedo electronics with out upsetting the rest of the car

It would appear it's only needed for distance traveled
There is an option for a wheel sensor

It should because satellite navigation works with time signals from satellites the clue is in the name

Has nothing to do with any cars speedo, you could hang the car below a helicopter and it would still know where it was

Sounds like you're wiring up the starship enterprise there my friend................

Stuart

Early Beckers also needed the speedo and reverse feed. They even supplied an adapter for the cable type. On the S2 I tapped into a wire behind the instrument binnacle but upgraded to an Indanapolis Pro which doesn't need it. Love Beckers they look just right. The 993 has a Cascade with a software hack to give speed camera warnings very handy on strange roads. Maps are pretty crap but voice direction good and accurate. I use the Iphone more as satnav.

I have tapped into the speedo sensor circuit to provide feed for an accurate rally trip meter on my oval dash '85. I connected into it under the boot carpet before it disappears into the loom and then ran the wire (together with additional permanent live and earth wires from the battery) under the carpet to come up beside the radio. Straightforward, didn't need to remove the dash and certainly hasn't interfered with the speedo/trip operation.

On a previous square dash car I fitted a Terratrip sensor onto the mechanical speedo cable under the bonnet.

Thank you, that is great info. Will have a look.


Edited to say that of course what I wanted was distance, not speed !