[928uk] [Fwd: 928.org.uk: 928 S4 earthing]

This is an enquiry e-mail via http://www.928.org.uk/
from:
St.John Walker 

Hi,

I've tried to log a query on your technical section, but I just can't work
out how to do that on the webpage.

Problem is the speedo works occasionally, tacho should read 800rpm at idle
but reads 200rpm, cruise control is dead (I've changed the sender in the
transaxle to no avail).
****che Owners' Club (chap called Adrian) suggested that the speedo and
tacho errors could be down to bad earth, any ideas where this earth might
be?

Cheers,
St.John