I have noticed a problem with the heater on my 2007 Supercharged RR.

The car starts well (although I think my battery needs changing as the voltage isn't as good as it should be - I am working on that at the moment) and the heater warms up great and pretty fast. The temp gauge is bang in the middle.
But after a while the heater goes much colder and I can't seems to get it to the same temperature as it was at the start, or even to a nice temperature. The car runs well.

Has anyone any thoughts on what to start looking at?

The car is new to me and before I bought it the dealer has the air conditioning serviced and refilled.

All advice welcome.

Thanks
Roger

I recently well this summer had issues with mine. and as the weather has cooled found when left in Auto the AC was too strong and the cabin was too cold, the solution was to turn off the AC but leave it in Auto. Also in the hotter months the AC was temperamental sometime it would cut in a col the cabin and sometimes it would not. I did have the system re-gassed and tested to ensure no leaks.

after some investigation on here and other sites the compressor which is clutch less has an electrical controller that fails while this part is cheap the effort to remove the AC compressor is not a simple task so i elected to replace it.

this has now fixed the issue and the HVAC system now works as intended, i leave the whole thing in Auto with the AC on (It defaults to this when you press auto) and get warm air when required in the cabin as you would expect. 2012 Vogue 4.4 TDV8 - Current
2014 Navara V6 - Gone
2004 Vogue TD6 - Gone
Grand Cherokee - Gone
Discovery V8 (LPG) - Gone
Discovery TD5 - Gone