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I'm just 'dry-fitting' all the bits onto my rebuilt shell before taking it all apart again for painting. Purpose is to make sure it all goes together and that all the necessary brackets/holes have been welded/drilled. (So... expect lots of question popping up here... apologies in advance.)

The wiring harness has a mystery extra 3rd wire (not on the wiring diagram) running from the interior roof light fitting. It would make electrical sense if it carried switched power from the overhead light fitting to two 'slave' light fittings - one at each corner of the shelf. But I doubt any Mini of the era would be produced with such a pampered interior. Not even the Countryman ("with heater"). But please tell me I'm wrong?

The purple-white wire is definitely original to the harness. The car is an early-'64 UK RHD smooth-roof Countryman, with floor-start.

I think that the 'spare'wire is the manual live for when the doors are closed and you want the interior light on. Very rarely used when car is used by a married couple but in regular use by single couples after dark........ So I've been told!

It's just the standard arrangement. Purple is the 12v feed from the fuses, purple/white goes to each door switch. To complete the circuit it is earthed through the door switch or when the lamp switch is operated (earthed to the black wire).

Although I agree, early 64 diagram doesn't have door switches so the purple/ white isn't there. Presumably yours is at the crossover point and doesn't have door switches but has the wiring for them.

It's there if the interior light has a 3 position switch, which I know they don't.

It would allow you to turn the light on from the switch on the light itself rather than having to open the door.

Which wire are you saying is "extra" ?, purple/white or purple? The purple/white is for the door switches and the purple is the feed. The early 64 diagram has no door switches therefore no purple/white wires.

Thanks everyone. A simple explanation that didn't occur to me - I didn't know early Minis had door switches at all.

I don't know if this example had door switches. Anyone know if floor-start estates would ever have had them?

The wiring diagrams show floor start, no door switches pre 64 then key start/door switches thereafter. That said there are never any definitive dates for changes so yours could have been fitted with the later harness prior to inclusion of the switches.

Though this is a hybrid harness: floor-start (because the main 12V take-off is taken from the floor starter switch - whereas the key-switch harness would have taken it from the solenoid) yet it also has the door-switch cable. I'll dig through the pile of bits the car came with... maybe I'll be really lucky and find a pair of Linread door switches.

Edit: no switches in the heap. And no holes for switches (the original metal where they would go is still present). And no witness marks on the remaining original door where a switch would have rubbed it. The explanation for the hybrid could easily be that a floor-start front harness was used together with a door-switch-equipped rear harness - the two parts being manufactured and installed separately.

111Robin wrote: ↑Sat Nov 02, 2024 6:11 pm Which wire are you saying is "extra" ?, purple/white or purple? The purple/white is for the door switches and the purple is the feed. The early 64 diagram has no door switches therefore no purple/white wires.

Sorry. If you have door switches, then the plain purple is extra.
If you don't have door switches, then the purple/white is extra.

Spider wrote: ↑Sun Nov 03, 2024 1:46 am

111Robin wrote: ↑Sat Nov 02, 2024 6:11 pm Which wire are you saying is "extra" ?, purple/white or purple? The purple/white is for the door switches and the purple is the feed. The early 64 diagram has no door switches therefore no purple/white wires.

Sorry. If you have door switches, then the plain purple is extra.
If you don't have door switches, then the purple/white is extra.

The wiring diagrams with door switches show solid purple as the lamp feed from the fuse box then purple/white going to the switches. Purple feed must be present with or without door switches.

111Robin wrote: ↑Sun Nov 03, 2024 9:11 am Sorry. If you have door switches, then the plain purple is extra.
If you don't have door switches, then the purple/white is extra.

The wiring diagrams with door switches show solid purple as the lamp feed from the fuse box then purple/white going to the switches. Purple feed must be present with or without door switches.
[/quote]

OK, these need the Purple and Purple/White Wire. The Earth (Black) is likely there for positive earthing of the lamp assy.

In operation, there's a live feed from the fuse box (Purple wire) to the lamp and then a Switch Wire (Purple/White) to the Door Switch.

Spider wrote: ↑Sun Nov 03, 2024 10:31 pm

111Robin wrote: ↑Sun Nov 03, 2024 9:11 am Sorry. If you have door switches, then the plain purple is extra.
If you don't have door switches, then the purple/white is extra.

The wiring diagrams with door switches show solid purple as the lamp feed from the fuse box then purple/white going to the switches. Purple feed must be present with or without door switches.

OK, these need the Purple and Purple/White Wire. The Earth (Black) is likely there for positive earthing of the lamp assy.

In operation, there's a live feed from the fuse box (Purple wire) to the lamp and then a Switch Wire (Purple/White) to the Door Switch.


[/quote]
The earth wire is there so you can switch the lamp on manually when the doors are closed (ie. no path to earth through the door switches). On a car with no door switches the purple/white is therefore redundant as the lamp can only be earthed through the black wire when the switch is operated.