Strange wiring problem

[cameron02]

I have a VDO electronic Speedo. Its been wired using the AUII XR8 wiring. The speedo seems OK but if I turn on the headlights it says Im doing 30 to 40 kmh whilst standing still. Turn the headlights off and its OK again.

My auto elec has been out and had a look but its stumped him.

Any of you wiring guru's have any ideas.

Oh yes. There is a light blue wire with a white stripe (called speedo out wire), no idea what to connect it to?

Any ideas?

[PCC]

Cameron,

Does not bring back happy memories - wires wires wires!

Assuming we are singing from the same hymn sheet you should have 3 wires coming from the speedo

Red Speedo sender power supply +8.2V

Light blue / white speed INPUT pulsed from 0 to 12V

White speed OUTPUT pulsed from 0 to 12V

I think you are earthing out somewhere.

The sendor power seems fine in that if it was more than or less than 8.2V it would not work (assuming it does when driving)

Why have you not got the blue / white wire connected??????????

This should run through to your tranny (along with the output wire (white)

Is it not the case that because you have'nt connected it your speedo is playing up???????

I must be a guru as I've given a half decent explanation!

Mind you, to become a gur you must first suffer the pain (99% hard work and 1% genious).

I have a wiring cluster table for the Chaser AUI XR8, which I understand is similar to the AUII XR8. Let me know your E-Mail address and I'll send it.

Good luck and stop looking at those dials - they send you MAD!

[trularin]

The silver wire must go to the sending unit, but more importantly is the red and black must go to power and ground. YOU CAN NOT common ground the black wire or the speedo will do strange things.

I hope this helps. I have the same speedo, but I have a Field Effect sending unit.

[cameron02]

Thanks for the help guru's

I think the common ground will be the problem. I asked my auto elec and he says he did try direct ground but did not disconnect the common ground at the time.

Peter, currently the blue/white wire is not connected because we dont know what to connect it to or where it goes to. We think it might be for the trip computer on the XR8 dash?

I'll let you know how things turn out. For now I am just going to get it registered as is.

[PCC]

Cameron,

Have you tried the Fordmod guys - you should be able to pick a schematic for your cluster and take it from there.