I know this has been covered before, but I have been suffering this inconvenience. Have spent some time this afternoon investigating battery voltage, earth and exciter wire to the starter. Checked for voltage drop on these when the dreaded “click” occurs. Of course it was reluctant to fault ! The exciter lead from engine fuse box to starter solonoid appears to be the issue : when starting normally there is a drop of 0.70V which I would consider to be high. When fault manifests the drop is 2.75V, battery voltage at around 12.1V . Measuring resistance of the open circuit wire does not show an issue - no load.
Next step run a new wire in a see where we go. Any one got any more thoughts
Cheers
Q

Could be along the right lines. The cables were poor quality and suffer degradation. As cabling is cheap, a good place to start / a good bit of preventative maintenance to do regardless.

Not had an issue on my RR, however I had a simar fault on my boat. The voltage was dropping c.2.5V to the starter. Tested the cable and the resistance was quite high. Replaced with a new and proper marine tinned cable and normal service resumed. 2015 Range Rover Autobiography 4.4 SDV8

I’d love a how to guide to replacing these dodgy cables Gary  2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90 on order so "Rory" will be going to a new home....!
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
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Is this the main high current wire to the motor or the smaller wire to the solenoid?

Thanks.

The smaller wire to the solenoid

Thanks.