Air intake "Summer/Winter" lever?

[agentdagnamit]

There's a lever on the left side of my new Bongo's air intake. 2 positions, forwards and back. Some quick googling suggests this is a summer / winter switch.

Can anyone explain more about this to me, and which position is summer vs winter?

I have noticed that the heater doesnt really blow hot air until I turn the temperate control up to over 30c.

Thanks

[g8dhe]

http://igmaynard.co.uk/bongo/forum/view ... 05#p593605

[David Edwards]

Never had one on mine, is that an auto box feature only I wonder

[Simon Jones]

It's fitted to the later models. Good excuse to buy one