heating probs

evening peeps,
another prob with the bordeaux, the heating is playing up again, when blowing heat the hot air is only blowing through the passeneger side vents, cold is blowing through the drivers side vents, ok if your being chauffered not if driving.
this problem may already be answered on here but been through ten pages and not seen anything.
much thanks in advance
glyn

I know nuffink about Rangies - but the usual answer on Rangie heating issues is "Blend motors" - mite be worth looking for threads on that subject.