Heated Door mirrors on 04 Symbol

Hi all,
       Got swiped by a lorry in Dorset last week, as a result got a broken mirror glass on my '04 Symbol though mirror housing & elecs are OK.

Got new (unheated) glass on fleabay, removed old broken one & to my surprise it has a heating element wired to it.

I've driven many miles over the years in this van & didn't realise it had heated mirrors. But how do they operate?, There's no controls that I can see & no mention of heated mirrors in the owners handbook.

Anyone out there with a similar age Peugeot Boxer Symbol that can throw some light on this?

Our Pollensa on a 2002 Peugeot Boxer base has heated door mirrors, these are operated by a switch on the dash which has the symbol for a rear screen demister (which obviously we DON'T have!).

In many cars/vans the heated mirrors can be made to come on automatically when you turn on the heated rear window, and they typically turn off automatically after a short timer.

On mine it's an option in one of the body control modules, though by default it's not enabled. My guess is that if your van doesn't have a HRW, they don't bother to go to the trouble of fitting a different (non-heated) mirror - the extra cost is probably more than offset by only having to stock and fit one type.