On cars between 2009 and 2012 the air conditioning either does not cool enough, or it occasionally drops out completely. The Golf Plus is sold in winter too, and a faulty air conditioner does not show in the cold.
What to check
- Set the air conditioning to maximum and let it run for at least ten minutes
- Try it in winter too: the compressor has to engage
- Listen for the compressor engaging: a click, then a change in the revs