Thread: Electrical wiring problem.. to oil pressure switch on Td5

And I thought 2021 was going to be a better year than 2020.
This is not a good start...but still only a first-world problem.

I have a year 2000 Td5 auto that I bought New and have personally serviced since.
Been doing some long overdue maintenance like machining warped exhaust manifold and replacing engine mounts etc etc.
Looking at the Wiring to the Oil Pressure switch ( on the housing that holds the spin-on oil filter...under exhaust manifold).
It is all stiff and brittle due to heat/age and the split-loom conduit covering starting to disintegrate, so I (foolishly) thought I would replace the conduit where it runs behind the back of the engine block.
Whilst removing the old conduit I find one of the two wires is broken.
That's easy I will solder join it. Ah no!

Here's my problem.
There are two wires to the Oil Pressure Plug.
One White , the other Black.
The White one is in tact and runs behind engine and over bell housing and into the main wiring loom ( on the drivers side, rear of engine under fuel cooler).

The Black wire has broken, and the length I have at the Plug end is only about long enough to reach eg the middle of the bell housing and probably not the driver's side of engine block.
That's easy I will go to the drivers side of engine and find the other half of the Black wire. NO!
So I start un-peeling the loom where the White wire enters..still no trace of Black wire.

I download the wiring diagram for Discovery 2 and it shows every engine sensor relating to engine management ( eg fuel pressure /temperature MAF etc ) but I can't seem to see the Oil pressure circuit? on either the Power or Earth distribution circuit diagrams.
But then ( at almost 74 ) I am now getting older and stupider..whist my Forgettery is improving.

I need a little help please, from those who understand all this electrothingamajiggery.

Firstly. is the Black wire simply an earth return to complete the switch circuit? If so I can bodge that.
Or is it "live" ( OK, so I haven't yet tested the White wire)

Secondly. can anyone please point me to the correct bit of the wiring diagram that shows the wiring path for the Oil pressure switch.

Any assistance greatly appreciated.

Thanks
Bob

Still a Land Rover tragic:
Range Rover Classic 3.9 "Sherwood"
Range Rover Suffix A, 2 door & stage one Bubble-cab ute V8.... both undergoing slow restoration.

Pretty sure it's a rite of passage, you aren't the first and you're definitely not gonna be the last.

I'll possibly save you some more stress, if you've got some odd wiring around your abs pump it's probably someone having done the hard wire fix for the shuttle valve connector.