FLASHER: Urs book , Vol 1, Electrics Chapter P178 cites the P241D, with a photo, perhaps incorrectly, as the connections including the mount tab are different from the 241D, and are not what I have seen on a 120, nor does the flasher seen on P177 with the single mount tab appear to be a “P241D. Some time back Roger Payne wrote: . . A June 1954 (car) … would have been fitted new with a Lucas FL3 flasher unit, albeit undoubtedly long gone as their marginal reliability had them superseded by the FL5 unit in 1956. Thus any Jaguar spare parts for failed FL3 received the upgraded FL5 replacement from 1956 on. …(and) invariably now have an FL5 unit fitted which is a direct physical/wiring replacement, replacing a long ago failed FL3.T he last of the USA market XK120s also got the Lucas FL3 unit, replacing the earlier Tung Sol 241D fitment, but I have not yet established exactly when that happened. I did pick up a NOS FL3 only a couple months ago - for my XK140 restoration, albeit will be interesting to see how long it lasts. (for originality) …the best solution if you can find an original, exc condition FL3 housing ( a lot of black ink artwork on aluminium canister) (with (or without) failed internals), is to retain the FL3 housing, and fit new FL5 internals (same diameter/shorter height - so with some effort, can be done). But you want an early FL5 with screw-type terminals, and not the post 1957 variety with spade-connectors, albeit both FL5 versions were made for spare parts supply well into the 1960s/70s so they can still be found.”
I note that On p177 the turn relay DB10 is shown with its tabs horizontal…I have seen it also tabs in line front to back. What have you seen. By the way…the turn relay box is now re-made by Lucas, in solid state for about $99 USD. I installed one such. Loo much the same…as with the flasher, for originality the new turn relay…can have an old original top case installed over the innards.