My wiring works OK if wired up as in the RH wiring diagram. Although this is not always 100% clear in some places.
I have used 2 large lucar connector blocks instead of the RH screw connectors. This is more reliable and allows easier removal of the dash. (lost count how many times I have done this so far). I also needed a good earth return to get reliable operation of the warning lights.
Best of luck
John
Anyone got any ideas about how to get the tacho working???