https://www.holdenmorgan.co.uk/parts/Classic_2014_v5.8_.pdfThe above link is to a Morgan parts book via Wolf performance website links page - its a huge pdf file that takes an age to load - but should help you locate a new switch if needed. Have you tried pressing it on/off a number of times? may help if its a dirty contact for example.
I think the fog light circuit may well have its own fuse too - worth checking first
on my car it works with dip and main beam.
The part number is ( Morgan) MDE15270 ( fog light switch). I would imagine any helpful Morgan dealer would be able to order one.
Typically you would use a rear fog light in conjunction with dipped headlamps in foggy conditions, so this must be an option. Whilst it may be dangerous to use main beam in heavy fog due to reflected light I guess it would do no harm to have the rear fog on as well if selected, in light misty conditions.
Rear fog lights are wired through headlamps so they extinguish with them to avoid accidentally being left on when not required, although I believe there is a warning light requirement when they are functioning.
On the Roadster and I believe +4, the rear fog is controlled via the BCU on command from both the headlight and fog switch. The fog lamps have their own fuse which feeds front ones if fitted as well.
Later v 6.0 version of MMC Classic 2014-on parts manual
here.
