Hi to all.I have a serious problem with heating which i am trying to solve for more than a year but with no luck so far.Problem is that for having hot air i must set both temp gauges at max temperature.If otherwise no chance for hot air.
Now if i try to reduce temp even by one degree let's say driver's side then driver's/central and back vents start to blow cold air.Only co driver's vent continue to blow hot.
Same happens if i reduce temp fm co driver's gauge,all vents blow cold air other than driver's vent.
By the time is blowing cold air even if i will reset gauge to max temp air remains cold.
I have changed all sensors/valve in engine bay and recently the viscous copling but nothing has been done
Any idea what else should i have to look for?????
Unfo RR authorised dealers here cannot help me since they just changing parts without any result

I had a similar problem. For me, it was a problem with the heater flap. This flap is actuated by the dial just under the center vents ( on a 2003 RR ). This is the dial with blue and red dots. The dial pushes and pulls on a cable which, in turn rotates a cam located on the passenger (right) side of the center console, down low, right where the heater duct for the passenger floor connects. I had to remove the glove box to get access to the screw holding the cam on.

If a passenger accidentally pushes on the heater duct with their feet, the duct can come loose and cause the cam to disengage with the pin which moves the flap. My car was blasting cold AC, despite left and right temperature knobs set to their hottest settings.

Click image to enlarge

etischer many thanks for your reply but think that rotor with the blue and red dots should work since if u will shift from 3 red dots to one red dot then u can feel that air is coming out is less hot.(but still i will give a check)
Problem is that for having hot air both temp knobs in heater panel should be turned to 28 and if try to minimize temp even by one degree, from either of temp knobs, then air is turning to cold.

Are you sure that the valves controlling coolant to the heater matrix are working properly? Or that they are gettin. The correct signal. I found that the heat of the engine made the connector and wire brittle. V8 or else ...

Fisha thanks.Valve controlling coolant to the heater matrix has been replaced.Now donot know what about connection/cables.I suppose the guys in workshop when replaced valve if they had seen something wrong with cables would mentioned or not????
I will have a check my side

Many thanks

My thought is that when on full hot, it'll be sending a full voltage to the valve and any mid setting will be a proportion of that full voltage. If the wiring or connection isn't just right, then that proportional voltage may not be getting to the valve right, and so no hot coolant through.
Was just a thought. V8 or else ...

Fisha it' sounds to me quite logical/possible considering fact that i have changed too many things without any result and this is the first i will check on weekend.Can it be so simple?then

Fisha checked plug/cables in valve and seems to be quite ok.Wondering if there is any possibility to be something wrong with heating control panel.I have noticed whenever tried to reduce temperature and system in auto,the blower speed increased.is this normal???is there any way to be checked????
For me its unbelievable that i have visited a lot of authorised dealers and noone has found the problem
Another symptom is that even when car is hot i push auto to start heating but cold air is coming.i have to close it and restarted few times and then starting to blow hot air????????????????
I am starting to fed up with this car