Another TD5 with starter problems!

This seems to be a common thread, but so far I haven’t spotted anyone with the exact same symptoms. It all started after a genuine starter failure. Factory original as far as I can tell, so almost 20 year’s service – can’t complain!

Before I go into the details of the issue, just to say she’s a 2006 TD5 Defender with factory (ECU) alarm and immobiliser. She has already circum to a wet ECU loom (replaced 2017-ish) and a bad earth.

So, the starter motor finally died. Solenoid was clicking away, but otherwise dead on the bench. Decided to just replace it with a new starter. All good for a few days and then the starter failed again. Very quickly diagnosed the new starter was fine. Eventually found that wiggling the solenoid wire to the starter fixed the issue. Connector looked gammy, so replaced it. All good for a few days, then same issue. Wiggling the solenoid wire still seemed to fix the issue, so investigated further. Copper looked a bit green, so trimmed the wire back and replaced the connect again. Gave the loom a good shake – problem solved.

One week later same issue!!! So, I’m pretty happy with the earth, and the ECU is bone dry. Wiggling the solenoid wire no longer does the trick. I’m assuming the yellow relays have a green LED inside them, as when I turn the ignition I can see the rely flashing.

All the dashboard lights come okay, NO CLICKING from the actual starter. Last time I had a bad earth, my temperature gauge would max out. This time all the gauges are behaving themselves.

I have a horrible feeling we’re heading towards a new loom – any thoughts?

It is (like many TD5's) experiencing electrical issues.
Why this is so common/bad is a mystery (to me at least).

If the wire inside the cable looks 'green' that is copper oxide which is a clear sign of water ingress.
Unfortunately this makes the wire brittle and it will often be pulled apart inside the plastic outer.

The relay has a gtreen LED inside ? I'm not sure about that, this could probably be an arc, which again (unfortunately) is detrimental to the relays operation.

Can you try to connect the solenoid wire directly to the input side of the relay (essentially bypassing it) ?
If that works the relay is gubbed.
If not try a new wire direct to the solenoid, if that works, it's the wire that need replacing.

Agreed, definitely worth a bit more testing in that area. Just wanted a sanity check that the fault wasn’t hiding somewhere else! I might just swap out the relay anyway – try and narrow it down to the wire.