Mystery switch and a flashing light.

I suspect I asked this question some years ago but have forgotten the answer. (No ageist comments please )

Warwick Duo 2015. Under the driver’s side bench on a wooden upright panel near the boiler is an illuminated switch. What is if for? The manual is silent. Looks vital but I know not why.  Also on the rotary switch having put the boiler on water on electricity I get an amber flashing light in the 8’o’ clock position. The book tells me amber means heating up but nothing about it flashing. Thanks in advance.

Bob
The red light below the bed seat, is for the frost prevention switch on the tanks below the van.

Of course I remember now. It’s in addition to the one by the door. Thanks Brian.

Yes  - near Door switch for fresh tank's heater pad; most awkward to reach switch is for grey water heater pad. Never used either....

Can't help re amber flashing light. My (same year) van doesn't have an amber light as far as I know. I assume yours is a Truma?

Cymro

Thanks. I’ve  never used either…either. Yes a Truma. Anyway it’s going in tomorrow to have a new roof light fitted; not the ones with the winding handle but a simpler push up version. I will get them to look at the boiler controls. I should have added it doesn’t heat the water on electricity. According to the manual a flashing red indicates a fault but this is definitely amber.