Disco 2 DICO TD5 WILL NOT CRANK

2004 Discovery 2 TD5: starter will not crank. But starter is fine, solenoid is fine, starter relay is fine, spade connected wire on solenoid running up to engine bay fuse box is fine, two different ignition keys tried to no effect so assume that is not the problem.
Vehicle can be started by bridging across solenoid. It can also be started by removing the starter relay and bridging the two opposed female spade connections, which is what I have to do all the time until this is solved.
Appreciate any input here, thanks.

bindi said:

2004 Discovery 2 TD5: starter will not crank. But starter is fine, solenoid is fine, starter relay is fine, spade connected wire on solenoid running up to engine bay fuse box is fine, two different ignition keys tried to no effect so assume that is not the problem.
Vehicle can be started by bridging across solenoid. It can also be started by removing the starter relay and bridging the two opposed female spade connections, which is what I have to do all the time until this is solved.
Appreciate any input here, thanks.

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Have you tried a known good solenoid in place ? Or fitting a new relay ?

Dippypud said:

Have you tried a known good solenoid in place ? Or fitting a new relay ?

Click to expand...

Given the starter works properly when shorted at the solenoid, and also that it starts perfectly when the relay is removed and the opposing female bayonet fittings are shorted, starter motor and solenoid must be OK.
The starter relay has been swapped with other similar relays but the problem remains, so it cannot be the relay itself. The relay has been checked and works OK.
The brown wire with red stripe that runs from the solenoid bayonet fitting into the engine bay fuse box has been checked for continuity and is OK.
However, though the starter relay clicks when tested out of the car it DOES NOT CLICK when fitted in the car, so the start signal is not getting to the start relay.
It doesn't seem to be the key on my reasoning at least.
I'd be happy to be proved wrong Dippypud, and call me Craticus if I need a name.

bindi said:

It can also be started by removing the starter relay and bridging the two opposed female spade connections, which is what I have to do all the time until this is solved.

Click to expand...

Then if the relay was ruled out the problem is with the circuit to the relay's coil from ignition, can be the ignition switch's crank contact o something beyond that until the relay's power pin, troubleshooting is needed on that path... did you check fuse F23 interior fusebox? if it's OK take a live from any fuse with a wire and insert it from behind into that brown connector(which is on the front of the interior fusebox) where the white/red wire is with ignition on 2... if it cranks this way the ignition switch is fubar, if not i can tell you more but only if you have enough electrical knowledge to work with diagrams