Hi,
I cannot find any earthing diagrams, but I would have thought it would be close to the unit. Check to see if it is earthed via one of the fixing screws. Otherwise try running in a separate earth wire from a convenient location.
<h5><font color="black">Dave.
Marea HLX 2.0 20v</h5><h6>Airbox with attitude[8D] Blue Momo Tomahawk Gear Knob, Blue stuff
Ecotek fitted, removed and waiting for warm weather. Only getting 23.5mpg
So much to do, so little time.... and Totally Skint!! </h6></font id="black">