Series 2 XJ12 Instrument Lighting

I am a person who likes bright instrument lighting but this is not an XJ or Etype strong point. My fuel gauge is a dull white, temp is bright white, speedo is a beautiful green and the other gauges are white.

Clearly my gauges are in need of some refurbishment.

I have a spare set of gauges so I intend to refurbish these and put them in - intention is to carefully clean, paint the insides gloss white, replace or recolour the coloured moulds and replace the bulbs.

Is there anything else I should be looking at? I would like to replace with LEDs but only if it is straight forward - any suggestions on what to use.

Also while on instruments, my original handbook for the car does not have a light in the bottom right of the tacho - opposite the left turn indicator - where both of my tachos have a red/orange light there - can someone enlighten me what this indicator light is for.



as you may remember i have an xj6 s2, i by passed the dash light rheostat 'cause i never bother to dim, replaced all globes including the idiot lights with led’s including modifying fiber optics, the orange light is for rear demister warning,…my xj6 doesn’t have the orange light in the tacho, that spot is blanked but it’s in the speedo

Clean everything including the ground connections and if it’s still too dim for you bypass the rheostat; a bright led in the opticell is good, but I would keep the incandescent ones in the instruments as they drive out the moisture. Also, they are more reliable than LEDs.
You could remove the green filters to get white light. If you like green you have to find filters or green LEDs. The alternator light should be kept incandescent, and one of the oranges is for the deftroster, the other the bulb failure unit (at least on the series 3).

Thanks - yes there is the orange demister light in the speedo - looking for what the one is in the tacho.

same thing on the tacho different model

Thanks David - going into an El Nino weather pattern in Australia, moisture in the instruments is not an issue - already getting to 30c for a few days and only the second week in spring.

From your comment I guess there is a design issue with the rheostat if it is not passing a full 12v through to the instruments when it is turned right up - can be sorted with a good aftermarket variable resistor.


Sorry Tom - not following that. I have the left indicator light and this red/orange light in the tacho and the demister light and right indicator in the speedo.

I thought the light might have been the indicator light for the fog lights (as this is probably required by our laws) but nothing comes on when the fogs are on.


most likely rear fog but mine is blank on the tacho & the demist is in the speedo, rear fog as fitted to some markets with a separate switch, in the schematics i reproduce it is listed as a rear fog guard switch, red/orange wire to switch to red/blue wire to lights. i do you have the aus document for lighting requirements but haven’t looked at it yet. will tomorrow but i’m not aware having to have a warning light for front fogs

When I lived in NSW and had additional lights, the road worthy inspector always looked for a switch, a indicator light and for driving lights, that they worked through the high beams. Remembering it is still a fine for having fogs on when there is no fog so a dash light was there to remind the driver they were on.

My current daily driver has dash lights for the front and rear fogs.

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I bypassed the rheostat with a simple jumper in our 1990 V12 Vanden Plas and 1990 XJ-S convertible and this made a significant improvement in the brightness of the instrument lighting in both cars. The lighting was improved so much by this simple yet easily reverseable modification that I no longer considered changing to LEDs. I have posted about this a few times on the Jag-Lovers XJ and XJ-S list so information about how I did this and pictures of what I did are available in the archives.


Thanks Paul - helpful to know :+1:

And rightfully so, Garry - driving behind someone with the rear foglamps ‘on’ in clear weather drives you nuts…

Less of a problem up front where the driver can see what is lit. And in US there were not rear fog lamps fitted, and no fog setting on the light switch. So the warning lamp was not fitted.

Fogs fitted front and rear would be driven by the same circuit - with a single warning lamp…?

xj6 85 Sov Europe (UK/NZ)

While my XJ12 has standard front fogs, it does not have rear fogs.

I have received a lot of great information on how to improve the instrument lighting, it would some in most locations around the world the little indicator light on the bottom right of the tacho is blanked - yet the one I have has a red/orange light and the spare tacho I have that I bought 30 years ago also has one. No one seems to know what they are for - maybe I have the only two tachos with them fitted :roll_eyes:

I have a morning tea run on Thursday with another Jag Club so hopefully someone has an XJ12 there and I can resolve this little mystery.

Thanks to everyone for their comments :+1:


Hello Garry,

To help you solve your mysterious light in the tacho: this is the “Choke” light, for cars equipped with carburetters :wink:



I thought that was V12 only, but is it the same on a Stromberg XJ6?
Edit I see this is all about XJ12.

To be honest, I don’t know for XJ6s but I understood from the subject title that Garry owns an XJ12
Edit, you edit while I was writting my answer :wink:

Absolutely correct, and I think you solved the ‚mystery‘ :slightly_smiling_face:!

May be onto something there - might also explain why there is no description next to the light as there is on the other 3.

Seeing is does not do anything in the XJ12 inj I might turn it into a low low fuel light which will be welcome addition.

To answer your question about LED, yes, you can replace all your bulbs by LEDS without any modifications. Dashboard / Gauge Bulbs – Classic Car LEDs Ltd Here is an exemple of products that can be fitted, you can also find some similar products on Amazon

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Part of Jaguar philosophy was to equip all cars prepared for all markets at the time of production for all eventualities. Like relevant wiring was installed, but ‘unused’ wires were not connected - and the same was maybe done with instruments. Ie, since the US market did not have the ‘fog’ position on the light switch the warning lamp was not connected, though ‘blanked off’ may also be the solution…?

As Jean Bapt rightly remarks; choke warning lamps were fitted when appropriate - but whether extra lamps were fitted in addition to the fog warning, which basically covered only rear fogs, or the fog warning lamp was used instead for this purpose is uncertain. Different speedos/tachos may certainly have been used over time to cover changes as years went by…

But if your spedos/tachos have the spaces required; a bit of rewiring either way may be possible…?

xj6 85 Sov Europe (UK/NZ)