The heater (if you can call it that) and de-mister (on the SII) has a valve under the engine bay to turn it on and off, for summer and winter, with plumbers piping solder etc, very high tec, my “A/C” is 2 front vents that open up, (good for getting fly’s and wasps in your teeth, but you can get an optional extra..... fly screens!! (I kid you not!!) and panels that don’t fit so you get a draft 
