As with any electrical wiring loom in a car there are many earthing points
all around the vehicle, however there is no 'list' as to where these will be,
and that is true for any make or model of vehicle.
Mechanics/electricians (NO...not dealer 'technicians') who work on cars will
possibly be familiar as to where some of these earthing points should be, but
again that does depend on which cars they have worked on or work on the most
and for what reasons. (such as audio/lighting, and charging)
With Main Dealers, their 'technicians' are not trained or taught how to repair
anything, instead they are expected simply to replace things until the problem
is resolved. There is no skill in that.
So if they get a vehicle in with electrical problems they just replace parts, including
sections of wiring loom until the problem is sorted as it is deemed quicker, less
time consuming and more cost effective (wages bill) for the Dealer; rather than
take the time to have someone investigate/search for/and repair the problem.
This means 99% of the time a simple repair is NEVER undertaken. The failure of that
method is that more often than not perfectly useable working parts are replaced in
an attempt to get one step closer to where the real problem is. And the net result
is that the customer gets to pay a mega bill for replacement parts that didn't need
to be replaced. This has been the 'modern' trend for at least the last 10-15 years,
and why Independant Specialists can and are better to go to.
