trouble with '95 audi a6 tdi speedo

Assuming it's an electronic speedo, the fault's far more likely to be the sender than the head. Hopefully on a FWD it's easily accessible.

Sounds like the sender in the gearbox. Whilst driving clear the average speed on the trip computer, if that stays at zero or doesn't vaguely match your speed then the fault is before the speedo

In which case

Remove instrument cluster

- Remove red and green 26-point connectors from instrument cluster

- Check connectors for bent terminals, repair as necessary

- Connect adapter harness VAG 1598/4 to red 26-point instrument cluster connector

- Connect adapter harness to instrument cluster and VAG 1598 test box

- Reconnect green 26-point connector to instrument cluster

- Set digital multimeter (Fluke 83 or equivalent) to AC (alternating current) volt range

- Connect multimeter between sockets 8 and 14 of VAG 1598 test box

- Place transmission in neutral and apply parking brake

- Raise vehicle on hoist

- Switch ignition ON and slowly rotate wheel Voltage must vary between 1.0-4.5 V (vehicle speed signal from speedometer present

If there's no voltage or it doesn't change the speed sensors dead or the wires from it are broken If there is an alternating voltage then either the speedo or the PCB's dead,

You can also check at terminal one of the 5 point connecter to the instrument cluster, terminal 1 is speed ~4mv, Terminal 3 is gnd & terminal

The speedo is not needed for the mot test.

MrCheerful

Yep, unplug it, press the catch & it pulls out, don't lose the sealing washer.

Crikey. Do you really need to do all this just to check the sender? Isn't there a connector near it?

Actually that's the easy way, it takes about 30 seconds to get the instrument cluster out & it amplifies the signal for you so you can see it on a multimeter easily. It also let's you work out whether the speedo or the pcb's at fault.

test thitis a test message!

this is a test