Dodgy Speedo

[bloopeta]

I have a 2000 golf GTTDi, most of the time my speedo doesn't work, and sometimes I can be sitting parked with the engine running and all of a sudden the needle will be bouncing all over the place, sometimes when driving it will start bouncing right round the clock, and then will stabilize and work for a while, usuall until the engine is stopped, but upon restarting it isn't working again.  Anyone have any ideas??

[rubjonny]

sounds like the cable has worn through somewhere and is shorting!

[bloopeta]

any ideas where?  how does the speedo work on one of these? is it a transducer on the gearbox or something??

[richandhazel]

Sounds like a bad connection somewhere. I think you'll find the speedo is electronic with a speed signal coming via the ECU. Out of curiosity, does the radio play up? Go loud then quieter? That uses the speed signal to compensate for road noise if you've set it up to do so.
Might help in your fault diagnosis

[bloopeta]

The radio used to go loud and quiet when slowing down etc, but that was with the standard gamma unit, i have an aftermarket kenwood in now

The speedo doesnt work at all now, it hasent done for months

[richandhazel]

Been doing some searching around to see if I could find anything to help. Firstly, if you can, I would carry out an autoscan with VAGCOM and see if any fault codes have been latched on.

I found this which may give you some idea's:-

http://forums.tdiclub.com/showthread.php?t=153220&highlight=speedo

http://forums.tdiclub.com/showthread.php?t=127367&highlight=speedo

Hope that helps.