MM 1000 Traveller

[nutmegct]

The overhead light in my 1957 Traveller doesn't come on.

The bulb tests ok (filament continuity). I dropped the fixture and found *three* wires: black, brown, and purple. The various wiring diagrams show only two: black and purple.

interior light.JPG (359.9 KiB) Viewed 806 times

I cleaned the terminals, but using my VOM with one wire on chassis ground, I get no voltage from the purple, and no ground from the black (or brown) - like they're not connected to any part of the harness. Regardless of fixture switch position, regardless of ignition switch position.

Puzzle: why three wires, not just two?, and why no continuity for the black or brown, and no voltage from the purple?

Thanks.
Tom M.

[ManyMinors]

Maybe the wires are not connected to anything? The purple wire is the live feed from the fusebox. Is the fuse dirty or blown? The light is not fed through the ignition so should work without the ignition being on. The same fuse powers the horn as well. Is the horn functioning?
The introduction of 3 wires came later, when the door courtesy light switches were introduced. A 1957 car shouldn't have this facility but perhaps has been added to your car?
You'll just have to find why you have no current - and no earth.

[nutmegct]

Thanks MM. A puzzlement indeed.

The horn works, and both fuses are whole and clean (as are the terminals).

I may be at the impasse of "do I really need the interior light?", as I don't want to pull wires under the roof fabric, and I've been down the rabbit hole of tracing old wiring with other cars.

Does seem strange that neither the black nor the brown seem connected to anything. Seems I should be able to trace earth from the black to any other earthing point.

The trafficators were physically removed years ago, sadly, and an electric blinker circuit added. Said blinkers work correctly. But still, the black earth wire for the interior light should certainly be connected to something!

The mind boggles.
Tom M.

[jaekl]

The purple wire comes from the fuse box but not as a continous wire. There is a connection under the right glove box. There should also be a connection for the black wire. Check those and the other end. The purple as stated starts at the fuse block and the black end somewhere on the bulkhead, engine side. The connection under the glove box is there so that convertibles could use the same harness.

[nutmegct]

Thanks Jaekl.

Are you saying I should find a purple wire connector, *and* and black wire connector, under the driver side (right side) glove box?

Any idea what that brown wire is for?
Thanks.

Tom M.

[ManyMinors]

On my Traveller, the earth wire was short and connected to one of the roof joint bolts.
The brown wire would not be fitted to a 1957 car originally but it is connected to the courtesy light switches on later cars. Either it has been fitted later to your car or your car is not a 1957 model.

[jaekl]

Yes, you should find two single barrel connectors (if the wire ends are bullets then wouldn't the connectors be barrels?) under the glove box. I will qualify that with I know for certain they are there for saloons and cars with doors switches, but it wouldn't make much sense to make a special front half of the harness for travellers and the door switches have nothing to do with these connections. Do you have door switch holes in the A post in the top part of the vertical section? I think they were introduced in 58. I know they were there in 59.

[nutmegct]

No door switch holes on the A pillars. Also, British Motor Heritage confirms my engine and body came off the assembly line in September of 1957. So, my interior light fixture must be a replacement, altho' the 1957 shouldn't have the brown wire up in the roof area! Still don't know what purpose that brown wire on the fixture serves.
Tom M.

[simmitc]

That doesn't look like a standard light fitting to me. Also, surely the Travellers all had the light fitted just aft (behind) the join in the headlining, not anywhere near the mirror (which also does not look original - nothing wring with that, though) or was there a different design on the earlier cars?

I suspect that a light has been acquired from a donor vehicle and the wiring adapted. One would need a supply wire, an earth wire that allows the light to be switched on manually and a third wire to go to the pillar switches for automatic operation. If you do not want automatic operation, then you just need a supply and earth.

Using a multimeter, check which wires are earthed and which have a supply on them. If you have no supply and no earth on any wire then just locate the other ends - they must come out of the windscreen side pillars behind the gloveboxes, and use whichever wires are most convenient for what you want. Do try for some consistency with convention, so use the black for earth and the brown for supply if at all possible, and insulate the ends of any unused wires.

Edit: Since writing the above, I have managed to find some pictures of split screen Travellers and seen that some do have the interior light nearer the windscreen, but the detail is not sufficient to see the design. I've only ever owned and worked on 1961 onwards Travellers; so, as someone wrote on another recent post, everyday is still a school day, even after 45 years of Minoring.

[Mr Spigot]

Having just fitted an early interior light (as shown in the top photo) to replace a later one which had disintegrated, I too was puzzled by the three wires. I connected them up as they appeared to be on the later switch, only to get a spark and small puff of smoke when switched on! I then followed the layout from the original photo in this post and all is working! The earth wire is in the connection on the far left, next to the switch, then the purple feed and then the brown/green from the door switches.

I too looked at a wiring diagram which only shows two wires, a black (earth) and a purple to feed. However, looking at another diagram (Haynes), it shows the purple wire going to the fusebox (live feed) and the brown/green going to the door switches, which when you think about it, makes perfect sense.

I attach some photos below which may be helpful

[ManyMinors]

The correct wiring diagram is in each car owners handbook as well as the workshop manual. These are worth getting hold of but of course you do need the correct one for your car as changes did occur during production. As stated earlier, the courtesy light switches and that 3rd wire were introduced late in 1958. The wiring to them is brown and black, not brown and green The black tracer denotes that the cable has an earthing function.

[Mr Spigot]

The correct wiring diagram is in each car owners handbook as well as the workshop manual. These are worth getting hold of but of course you do need the correct one for your car as changes did occur during production. As stated earlier, the courtesy light switches and that 3rd wire were introduced late in 1958. The wiring to them is brown and black, not brown and green The black tracer denotes that the cable has an earthing function.

Thanks and you’re quite right that the wire is brown and black. I mistook the black for a well aged green. My owners handbook only shows 2 wires, but perhaps I should have looked further afield and it may not be the right one for the year.