the resistor is there to stop a blow lamp causing the alternator to stop charging it mimics the bulb which intern cause the alternator excitation and the diode to stop feed back on the alternator as in the diagram there is an image of a water damaged header from a window screen leek and also check if the diode has been fitted the correct way round
Cheers Kermit, I was thinking along the same lines regarding the diode. When b and d are bridged the light goes out and charges normally. I think for the cost of it I might as well just change the diode just piece of mind.
Good morning all,I just wanted to post an update of my vehicle charging woes. It has turned out to be a faulty alternator, being a new unit I assumed it to be good and it was my wiring causing the issue. I should have trusted my own work and looked a bit harder at the alternator. New alternator fitted and now perfect.Anyway,moral of the story,never assume antything!