Hi everyone ,I’ve got a problem with my heating , the passenger side is warm/hot but the drivers side is cold /really cold if I put the aircon on ay ideas would be very welcome

I had a similar problem.  Took it back to where I bought it.  They replaced the actuator (I think that is what is called), that moves plastic flaps that route hot and cold air to windscreen, feet, etc.  The unit is up the side of the centre console, but not easy to get to  There are a few you tube videos and other posts about this problem as I remember