03-02-2024, 02:58 PM
Hi Nick
That yellow wire appears to have got hot due to excessive current flow, possibly something that has been going on intermittently for a long time. It's also possible that the fault/short circuit that caused it has now gone away or been blown out. The lighter colours show overheating more readily of course. A poor connection will produce localised heat, which might discolour a wire at its end but not along its length as your pictures show.
That wire feeds current from the Dynamo output to the Field winding via the "Charge Rate" section of the PLC switch, in all settings other than Summer Half Charge when the Lights are off. Normally, you would expect no more than a couple of amps to be flowing through it which is well within its capabilities
PLC switches are simple and normally reliable, I have never come across one with an internal short.
At the PLC switch, it branches off to feed the Ignition Warning Lamp, via the black wire you mention. I'm wondering if there is or has been a short circuit between the warning lamp holder and the grounded dashboard metalwork. These lampholders have "cardboard" insulation which isn't that robust. The black wire won't show up so much if it is blackened !
The other possibility is that excess current is flowing in the green Field wire of the Dynamo, due to a short or intermittent short of the Field circuit to ground within the dynamo.
That yellow wire appears to have got hot due to excessive current flow, possibly something that has been going on intermittently for a long time. It's also possible that the fault/short circuit that caused it has now gone away or been blown out. The lighter colours show overheating more readily of course. A poor connection will produce localised heat, which might discolour a wire at its end but not along its length as your pictures show.
That wire feeds current from the Dynamo output to the Field winding via the "Charge Rate" section of the PLC switch, in all settings other than Summer Half Charge when the Lights are off. Normally, you would expect no more than a couple of amps to be flowing through it which is well within its capabilities
PLC switches are simple and normally reliable, I have never come across one with an internal short.
At the PLC switch, it branches off to feed the Ignition Warning Lamp, via the black wire you mention. I'm wondering if there is or has been a short circuit between the warning lamp holder and the grounded dashboard metalwork. These lampholders have "cardboard" insulation which isn't that robust. The black wire won't show up so much if it is blackened !
The other possibility is that excess current is flowing in the green Field wire of the Dynamo, due to a short or intermittent short of the Field circuit to ground within the dynamo.