Early XK120 Windtone Horns: Fitting Instructions and Maintenance

As the cowhorn on my early '120 went missing under previous ownership, so did the horns. I got lucky recently with the purchase of a NOS pair still in their box along with wiring, a relay and the attached factory instructions. The relay has a date of February '49 so, I’ll speculate the contents were made at or after that time. These horns have the round trumpet. Anyway, someone here asked recently about how these are adjusted. Page 7 should answer that. I’m sorry I can’t rotate the images. Maybe another here has the capability to edit Adobe files?

20210304040626167.pdf (364.1 KB)20210305123203730.pdf (86.1 KB)

I love these original instructions.
Pull down the VIEW menu and click Rotate View and you can rotate it either way.
Do you have the mounting brackets?
horn bracket 014

Mounting brackets? You bet I do Mr. Reilly due to your excellent instructions followed by some time spent in front of the mill. Thankyouthankyouthankyou.

BTW, that gearbox swap in a previous post never panned out but if I ever come across a period saloon shift lever it’ll be yours gratis.


Do you perhaps also have pages 2 and 3 of these Lucas Windtone Instructions? I assume this leaflet initially contained 8 pages (including front and back page). Just to complete this very informative set.

Bob K.

Well that’s the office scanner up to it’s old shenanigans again. Sorry about that. I’ll get the missing two pages posted tomorrow.


I at least learned another word (“shenanigans”) that (as far as I remember) was not in my English grammar book at school. But then, we had to learn the “Queens English”.
Bob K.

I always thought it was Irish (Celtic origin) but a quick search revels that it also might be Spanish or English.

But I’d go for Irish - knowing some Irish people it fits well with the way they speak, and although my Spanish is almost non-existent it doesn’t sound Spanish to me. And it certainly doesn’t ‘fit’ English.

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As in- "If you don’t stop your shenanigans right now, I will smack you with my shalaylee. (Shillelagh.)

Original post now has the two missing pages added

I notice the instructions for 6V includes a relay but there is no relay in the 12V instructions. I wonder why not? My Mark V and XK120 both are 12V and have the WT614 horns with a relay.

Good point. On page two it says that when horn pairs are fitted to a car with 6 volt systems, a relay is necessary to limit the current carried by the contacts of the horn push and to minimize voltage drop by shortening the cables carrying the main current. Maybe Lucas felt a relay wasn’t strictly necessary on 12 volt cars, but Jaguar’s experience was that it was?


Using only 6Vdc they would draw more amps. Jaguar must have just decided to use the relay as well.


Christopher, Rob and Matt,

Lucas had the same recommendation when introducing the successor High Frequency horn range HF 1748 (like for the XK 140): no relay for the 12 Volts versions but a relay is required for the 6 Volts versions. See Lucas leaflet.

We know that Jaguar used a Horn Relay on the XK 120, but apparently now agreed with Lucas that a Horn Relay was not required for the XK 140.
We know that the WT horn type (in general) draws a much higher current than the later HF horn type, which is the reason Jaguar did not agree with Lucas for the WT horns.

Bob K.