1987 Series 3 Fuel Tank(s) Electrical Wires - Go Where and What?

[wgsouter]

Hello all,
I am removing the wiring looms from a 1987 Series 3 Donor Vehicle where I have some wires that are clipped onto the rear seam(s) of each fuel tank, that disappear down under each fuel tank - but what are they for and where do they go? Detail as follows ...
- Remove one Rear Light Cluster and there is a 4-Pin/Socket Connector each with a single wire: Black (presume Fuel Sender Earth); Light Green with Slate (presume Fuel Sender Feed); Thick White Wire with Green (runs under tank); White with Purple (runs under tank).
- Remove other Rear Light Cluster and there is a 4-Pin/Socket Connector with 6 wires: single Black (presume Fuel Sender Earth); single Light Green with Brown (presume Fuel Sender Feed); Two wires White with Purple (runs under tank); Two wires White with Purple (runs under tank).
As I cannot see down and around the fuel tanks and do not want to remove the side panels to get access to the fuel tanks - just to see where the wires go and what they connect to - does anybody know what the wires connect to?
Oh, another issue ... as I am colour blind, it is my best guess as to whether the stripes on the wires are Purple (might be Dark Blue) or Brown or Slate (might be Grey). The colour is not important to me as it is where they go and what they connect to.
The vehicle I am rebuilding does not have anything electrical apart from the fuel sender(s) ... what does the 1987 Series 3 have that is different? Is it important?
Anyway, pleased to receive constructive answers with thanks.
Regards,
Wolfgang Souter
Westbury, Wiltshire, UK.

[ChrisDixon]

Different to what, an earlier S3? Could it be the wiring for either the in tank fuel pumps or the changeover system?

[wgsouter]

Hello Chris ...
No, the Fuel Pump is in the boot - as is the Fuel Change-Over Solenoid. So, a mystery (to me) where these wires route down to. Hence, the question(s) posed.
NB: The feed wires to both the fuel pump and change-over solenoid are accounted for - they continue in the loom and exit inside the boot centrally by the antenna motor.

[mike020150]

Without poring over a wiring diagram, one quick thought comes to mind. N. American models had additional side lamps located not far from the positions described. Mike.

[wgsouter]

Hi Mike,
Good point ... I had not checked the US Wiring Diagram (didn't see these wires in the UK version). Unless mistaken, white is associated with a switched lightning circuit?
Regards, Wolfgang

[mike020150]

They often are. Mike.

[ChrisDixon]

I thought the S3 (and later S2) cars had submerged pumps. What is the donor car, 4.2, V12 ?