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Discussion Starter #21
Narrowing this down now as not the bulb but in fact looks as if the smaller cable from the alternator that completes that circuit is damaged between the alternator and the connection point at the back left of the engine bay you can access via the boot. On inspection the engine wiring loom from the alternator passes under the engine and is tucked into the subframe on the way to the starter motor. It's in fairly poor health and k suspect there's a damaged connection in amongst this loom that is causing my issue.

Going to test this at the weekend by hooking it directly from the connection to the alternator and will see where I get to!
 

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If an alternator doesnt self-excite- then it will not produce an output. About 15 years ago my son had an Escort that wouldn't see- excite- so I stabbed the windings with 12v and it remained excited, but obviously wouldnt when re-started. So, I fitted a cable from the starter-motor live solonoid switch via an 100amp diode and connected it to the field. The idea being that as the engine turned over- the field was energised. It worked a treat.- I simply didnt have the money back then to buy him a new alternator! He sold the car 3 years later with my mod still in place.
 

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Discussion Starter #23
Spot on Pat, I've learnt a lot about car electrics these past few weeks but this looks to be the root cause. I never could find the actual break point as likely buried in the wiring harness somewhere and I didn't want to risk messing about with that too much but suspect that it's been failing for a number of months particularly in the wet and hence it being an intermittent fault.

Managed to narrow it down to the cable I'd described, cut the old cable at either end and isolated with electrical tape. Sleeved some 1mm cable and used a butt connector to fix it to the exposed end by the engine relays in the boot routing it through the engine bay with cable ties to a ring connector at the alternator. Fiddly job and about £10 worth of bits but after charging the battery the car starts and the alternator is now charging!

Will piece it all back together tonight and get back on the road all going well.

Here's to making it through the MOT in March...

Thanks to everyone that helped out!
 
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