Anyone have a part number for a replacement Opticell bulb, or even an upgraded LED version?

 

Buy Better Car Lighting's LED replacement. IT vastly improved my XJS' heater controls etc.:
https://www.bettercarlighting.co.uk/...&productId=474.

 

Thanks Greg, I'll give it a shot. I assume that the dimmer function will not work, but that's ok.

 

the dimmer does not affect the opticell so a LED is fine.

 

I did exactly that, back in 2014.
Check it out.
LED 'bulb' I found was 5 LED elements, so it fills the reflector and makes all the switches readable.
(';')

 

Allow me to give my input as I'm currently working on the system in my car.
I found a led bulb with the required BA9 size and it works fine. You can likely buy them in any auto parts store as I did.
Only disadvantage is that the light isn't concentrated in only the longitudinal direction of the bulb.
I have a couple of alternatives on the way from a, believe it or not, sewing machine parts store. Aparently some Pfaff and Toyota sewing machines use BA9 bulbs.
Length of the bulb isn't an issue despite that was my immediate concern, and benefit of the LED parts from the light, is the low heat rejection. I tried a 21W bulb for a minute and it definitely
improves the system, but will likely melt the canister within a short time

 

it won't melt the case or canister but it will burn the tips of the cables, reducing light transmission. To fix this, pull each cable from the case and sand the tips smooth, to remove any charring.