G'Day Dennis, Happy New Year to you and yours mate!
I must admit I haven't had much use from the heater lately, as driving the vehicle these last few months, it's generally hotter in the cab than if I had the heater (or even two or three) on full blast anyway!
What's the advantage of running a fresh air sensor Dennis?

Peter
1974, 712 6X6 Pinzgauer
1983, 710-1.6 4X4 Pinzgauer
1997, 718 6X6 Pinzgauer (in pieces)
1971, 700 Haflinger
1974, 703 LWB Haflinger
2001, Range Rover
http://www.ozpinz.com