152/6 means that you are looking at page 6 of a particular engine type, in this case 2.0l diesel engine with start/stop system , CXFA,CXGA,CXGB,CXHA,CXHB,(7L6),(7MM) as shown on page 152/1
As far as I can see there is only one appearance of a G83 in the diagrams for that engine.
It obviously shows up on all other engines including the petrol ones so find the section that refers to your particular engine type, if you don't know that have a look at the registration document (V5C).
Reading current flow diagrams is somewhat of a work of art if you don't come from that type of electrical industry.