MK 4 tool tray light switch

The tool tray on the Mk 4 has a light linked to the side lights, but also with its own switch which, I assume, was a pressure type which came on as the lid of the tool tray was lifted. My car is missing this switch and I’d like help in finding out what it looks like and where it was situated. Thanks.


At least in the MKV it is in the middle of the tool trey lid bottom, so when you open the lid it will switch the light on, providing the sidelights are on.


The switch looks like these, but it is the one with the short plunger. It is mounted near the centre of the bottom edge of the boot lid frame, just above the wood tool tray. You should see a hole there with a mounting screw hole each side. Note the special insulating washer with the brass surround. If you are buying one which doesn’t have this, it won’t work. This is the part that makes the earth contact when the lid is raised.

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These photos might help as well.

Small red arrow shows the position of the switch on the lid.

(Excuse the temporary test wires !!!)

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What’s that funny round thing in the second photo David?

Is it the light? My '38 SS has a round one, but I’m missing the cover part.
light socket

The switch came in 2 lengths as Peter said.

The other was for Mark V doors and XK120 boot lids.

That oval lamp base looks identical to the MG T series dashboard map lights. They had to be turned about 45° to switch on. The covers projected quite a bit and may not be right for your application, but I don’t know of other types. They are readily available. They also had a cover for the ‘Thirtilite’ with a green lens which was wired into a switch in the speedo for switching at 30mph.

This pic, is 100% original from Oct 1947… so wiring aged accordingly, but note green paint over the countersunk screw heads, after switch was mounted…, and holes for the cables…

The correct/original Tool Tray lamp, as mounted underneath the lid, is shown below - from the same 100% original Oct 1947 Mark IV, but same as all Mark IV…

The actual Lamp itself is a Lucas TYPE FML.2 as was first introduced for 1940MY SS Jaguar, and continued on post war for all Mark IV 1945-49. See pic from Lucas Master Catalogue, showing lens and chrome surround, and their individual part numbers…

Thanks much! :wave:

Cant comment exactly on the MG T map light, base does look similar yes, but the cover is totally different… 1936MY SS Jaguar had no tool kit lamp at all, but this was one of the changes introduced for 1937MY - where a lamp was now provided under the lid to illuminate the Tool Tray/Kit… It was a LUCAS DF.41T - see picture from Lucas Master Catalogue…

Note, a completely different Cover to the Map Light, but also shows the distinctive oval base. Note these were used on all 1937-1939MY SS Jaguar, then superseded for 1940MY by the previously pictured FML2. Note with all 1937-1939 SS Jaguar, the DF41T lamp was mounted on an oval shaped block, allowing the switch mechanism and wires to sit proud of the flat tool tray lid and not recessed into lid, with appropriate hole and grooves in block for mechanism and wires. Dont have a detailed pic of Oval Block, but shouldnt be too hard to work out, with an original lid showing holes for screws and grooves for wires to switch…
See pic of an original DF41T mounted on an original 1938MY SS Jaguar - rather it was mounted, but now dislodged, with block missing but you can see mounting screw holes, and also route of switch wires hidden under the lining material from lamp to switch. Somewhere I have a photo of the wiring route with lining removed…

DF41T original

Ok thanks Roger. This T series map light may be the closest I can come.
I have the oval base. It is chromed BTW and about 3/4" high.

Thanks Rob, dont know where I got the timber base from - maybe someone I know made one out of timber as a restoration expedient. Bit I have had a more thorough look through all my 1937-39 SS Jaguar Tool Kit photos - LOTS! - and not many show the lamp/underside of lid (I have been blinkered by just the Tool Kit/Tray up until a couple years ago), and those that show ‘after restoration’ are not reliable, with all sorts of solutions/lamps now fitted, but enough to show that this oval base is made of metal, not timber. But impossible in my mostly poor photos to say whether maybe cast aluminium, or polished aluminium, or steel chromium plated - see one example…

Rob, is yours steel/chromium, or polished cast aluminium???

So I might have to check further in my many Lucas Catalogues - the DF41T is a MODEL, and yes this same DFT41T model was used for all 1937-39MY SS Jaguar, but whether the Bracket was always a 545149 and the Cover was always a 545114 remains to be confirmed, as amongst all my pics, although some lamps are clearly not DF41T, others look to be so, with subtle variations to Cover, as you will note with this latest pictured example. This one is a superb original 1937MY, but has had cosmetic attention. And is the base part of the Lucas supply (I think probably) or is it something SS Cars made themselves, or sourced elsewhere??? Anyway - we are way off the Mark IV topic now…

Thanks to all - most helpful!

Does anyone know a source for this switch - - in the UK?

Yes the round “thing” in my photo is my light which was originally in my 1948 1.5 SE MKIV when I bought the car for restoration.

Here are some more photo of my “dome” light pre restoration:

Interesting that fittings I’ve seen are either rectangular in shape whilst others are rounded (with a hole cut out in the tool tray to accomodate the taller dome of the rounded lights).

Here are some other photos of cars with the rounded lamps like mine. Lucas or Sparto spring to mind as the manufacturer of these dome interior fittings.
Boot tool box

Here are some photos of the rectangular lights:


Perhaps someone on the forum could suggest why the different types arose?

No doubt it’s women. If the design is a few years old they have to change it. :wink:

Here is my oval base. It is cast aluminum and chromed.

That red/orange sleeve seems to be original, near as I can determine. There are a couple more in other places on this car, like the ignition coil.

There is a curious angled slot in the socket, as if you could turn it to disconnect the center contact from the bulb contact. In fact I found it was turned, which was why the bulb didn’t work.

Back to the original question. Here is the info from the Mark V SPC.
You could search for Lucas 31185. It’s a very short stroke device. A long stroke wouldn’t work in a tool lid like it does with a passenger door.
Worcester Classic Spares doesn’t list it, but they might be able to get a used one.
Or there is Paul Beck Classic and Vintage Supplies.

Coventry Auto Components has the long one. They might know about the short one.

This subject came up on the XK forum a couple of years ago.

Coventry Auto Components or Moss Motors in the UK have the long stroke switches and rectangular lights. I did adapt a long stroke switch by filing off the end and spacing out the bracket.

Fantastic photos/detail Rob… hate to be pedantic, but you have lamp/base in hand, and you reliably know what you are looking at… Certainly it’s an aluminium casting, but I can’t easily reconcile the shiny outer surface being chrome plating??. No sign of chrome on underside/inside casting. Are you sure it’s not just a case of being highly polished aluminium, as is easily done, which may explain why others I have seen look more dull aluminium as per the base of yours… And in Jan 1938 for your car, and the earliest 1937MY introduction, if bright plated, maybe more likely just Nickel, albeit the same comment about not on underside/inside casting. No guarantees at all however that over the 1937MY to 1939MY period of use of this oval based DF41T Lamp and cast aluminium base, that there were not subtle evolving variations to finishing treatment, and indeed detail of the cover. I have a few other photos of originals, with cover missing exposing just the bulb and bulb holder, so maybe a weakness in the DF41T Lamp assembly… I think the one thing there is no sustainable debate about, is the fact that all 1937MY to 1939MY SS Jaguar (Saloons and Coupes) had this oval based Tool Tray lamp and its mounting position, as the receiving oval hole in the actual tool tray remains consistent over all original 1937MY to 1939MY cars, There is considerable evidence that 1936MY had no lamp at all, and the tool tray lamp was one of the features introduced with the revised 1937MY SS Jaguar. And my research to date supports a hard demarcation with 1940MY SS Jaguar, amongst many other changes to the Tool Kit/Tray, introduced the rounded-rectangular based FML2 lamp as found in all 1940MY SS Jaguar, all Mark IV and all Mark V. See pic of an original (and yes, very much unrestored) 1939MY Tool Tray and oval base DFT41T model lamp, underside view of course showing lamp base aligned with tool tray hole…

Your last two photos are Mark IV - thus correct as original rounded-rectangular Lucas FML2, and thus matching rounded-rectangular housing-hole in the tool tray, as introduced for 1940MY SS Jaguar, and used in all Mark IV 1945-1949 and Mark V 1949-1951.
Your first four photos are 1938MY, 1939MY, 1939MY and 1939MY Tool Kits/trays, which although there are variations in the tool tray itself between 1938MY and 1939MY, the oval based lamp, and the oval housing/receiving hole, and its exact position in the tool tray remains the same/unchanged.
As previously, nothing unusual about evolving changes with SS Jaguar and Jaguar. 1936MY had no tool tray lamp at all, 1937MY introduced the first Lamp - oval based, that continued for all 1938/9MY cars, despite other minor changes. Then major changes again for the 1940MY including introducing the rectangular based FML2 Lamp, and the revised rectangular hole in the tool tray. The 1945 Mark IV tool tray was only a very minor change to the 1940MY tool tray, and another minor change for 1946 to 1949, but all still with the rectangular FML2 lamp and receiving hole in tool tray…

Your 1948 1.5SE Mark IV - presumably a replacement Lamp installed at some time after 1948, and before you purchased the car. Does your tool tray have the expected rounded-rectangular housing-hole?