307sw136 heating

My 110hdi is the same. I use mine on manual and use the fan speed button to increase/decrease the air flow they are on the right hand side of the panel. I also find that i need to set the drivers side n2 numbers higher than the passenger side for best heating, although when the temp is very low (below 4c) my knees are cold and sometimes can be warmer with the drivers window open a couple of inches.