Should either be on / inside the clocks or directly under the clocks in the wiring. I dont think thats your problem though as it only alters / converts the speed pulse. I could be wrong. If you want the UK Clocks off me I can supply them, but for them to work you need the find the conversion chip and remove it otherwise speedo wont register anything.
Also plug in to diagnostics as these problems can be brought about from the meter amp or the BCM unit.
Where abouts in the country are you??
Call me and I will save you a fortune