sat nav install issues

[wils00]

Anyone know the best way to get the speed pulse wire to the back of in car sat nav. Trying to find wich wire i need ?

Any one whos fitted a unit let me know im fitting a blaupunkt travelpilot

[Brianmoooore]

Presume this is road speed signal we're talking about.
Don't know what spec of signal you need exactly, but the signal from the diff sensor arrives at the back of the instrument cluster, and I think a cleaned up signal is available at the green connector on the back of the cluster.

[Demlotcrew]

Yes if you have the green plug on the back of the cluster, it will output the needed pulses, there are three, one for the Cruse one for Speed sensitive radios and one spare.

Andrew

[wils00]

I have an 316i lux ( m40 ) this is a a late 1990 model I havent had chance to pull out the instument cluster as of yet but im hoping the green connectois on there , anyone know for sure if this model would have one fitted - oh yeah the instrument panel is the VDO version

[wils00]

you have said that the green connector on the back of the ip may be the crusie contol connector which will have the speed pulse wires i need. i have just pulled out the cluster to find 3 connectors on the back a blue on the right a white on the left , which i expected to see and i was hoping that that the green one would be in the middle at the bottom , thing is the connector that is ther is a yellow one, could this be the one i want?

[Demlotcrew]

Not all cars have them!

Its a add on you will need to buy the connector from BMW

Andrew

[wils00]

I have just had the whole lot out and have noticed that the yellow connector holds several wires including a brown red varient - which i think is the speed pulse wire. i have the clock/ temp sensor unit in my 316 as it is the lux and they just chucked this sort of thing in to spuce it yp a bit. Would i be right in thinking that the brown / red wire would not actual do anyting at the clock / temp unit and this is the one im after for a speed pulse?

[Brianmoooore]

Yellow connector is the only feed to the full OBC, which definitely needs speed information, so the wire must be in there somewhere.
According to my wiring diagrams, it's pin C (yellow socket) 26, and the wire is either brown/red or green red.

[Demlotcrew]

Thing is if you use that wire, the OBC will not give an accurate reading and the service lights will also not function to the set intervals.

The sat nav unit might also not get the correct feed.

Andrew

[Brianmoooore]

Thing is if you use that wire, the OBC will not give an accurate reading and the service lights will also not function to the set intervals.

The sat nav unit might also not get the correct feed.

Andrew

I would imagine the signal on C26 is of a sufficiently low impedance to be able to supply all that requires it, as long as the satnav input is of a reasonably high impedance.
Whether or not the signal waveform is suitable for the satnav, I wouldn't know, but it should be possible to construct a simple interface.

[Demlotcrew]

I dont know the input either, but i was advised not to take that feed (i have cruise and speed sensitive radio) because the OBC and service lights might be affected! (IE the lights will come on too late or too early)

But since i dont schedule my servicing according to the lights i dont know why im complaining!


Andrew

[wils00]

ok , I hear what your saying - you say you have a speed sensitive radio demlot, what wire did you use to hook that puppy up ?

[wils00]

Just got thinking a bit more , im think your right that the brown/red wire is using pin 26. i just dont see how this would effect the service lights though??? ( could be wrong though ) For example what happens if your motor only has the anologue clock instead of the poor mans 6 button comp or the 13 button comp. I have been under the impression that if you had no OBC of any kind that there would not even be a connector pluged into the bottom middle socket on the back of the IP. Surely the service lights are run directly from the blue or white connector?

[Brianmoooore]

Just got thinking a bit more , im think your right that the brown/red wire is using pin 26. i just dont see how this would effect the service lights though??? ( could be wrong though ) For example what happens if your motor only has the anologue clock instead of the poor mans 6 button comp or the 13 button comp. I have been under the impression that if you had no OBC of any kind that there would not even be a connector pluged into the bottom middle socket on the back of the IP. Surely the service lights are run directly from the blue or white connector?

The speed signal that feeds the service lights etc. is teed off, unbuffered, to C26, so loading this pin down could possibly affect the service lights.
Even if the input to the satnav or whatever is of a low enough impedance to do this, then it would be simple enough to add in a buffer in the form of an emitter follower or similar.