Earth point locations

Hi everyone,
Is there a chart or diagram out there detailing earth points?
Apologies if this has been dealt with before - I did a search but couldn't come up with anything.
2004 Defender 110 td5 XS.
I have an electrical fault which I feel must be an earth issue. Heater blower does not work;- If I link the earth return on the switch to ground the blower comes on, and reading the earth connector at that point to ground I get 35ohms - that would be a bulb somewhere I guess? Wipers do not work. When lights are off the temp gauge backlight comes on with the radio!! All seems to point to Header-Earth 0550(K108). But where is it?
I have the main manual and also the Defender 2002MY electrical circuit diagrams, but can find no reference to particular earth point locations.
Many thanks.

There should be an earth point behind the engine on the bulkhead on the drivers side, possibly the cause of the problem.

Just found the diagram I used.

Tonyj66 said:

Just found the diagram I used. View attachment 116167

Click to expand...

Brilliant, thanks Tony!

So, I have located the root of the problem... seems to be a "header" behind the instrument console with lots of black wires coming out of it. If I apply pressure to the wires, the blower and wipers start and if I wiggle it, they stop. Must be a dodgy connection within the header. Trouble is I can't seem to get it apart. Is there a special magic tool for this or is it brute force and ignorance. I've already ripped half my thumbnail off trying!
Thanks.

Can't help with that one. However, me, I would use a small screwdriver and slowly prise it apart, probably the wrong way to do it though!