Land Rover Repair: 98 range rover 4.6HSE, obd ii scanner, climate control

Question
our heat is not blowing through the heating vents.The book with the exclamation mark is on the LCD.We can hear the fan is on, we can feel that there is heat and cool air and all the heat distribution settings work but it not blowing through the vents? we had this problem a couple months ago and took it into a shop to be fixed and they replaced the ,relay valves.We also replaced the air filters.
It worked up until now. Could you please help us with what could possibly be the issue?

Answer
The most common cause of problems like yours is failure of the servo motors.  There is a set of three motors that operate the flaps in the air box to regulate hot/cold and where the air comes out.  Replacement of those servos is a full day's work, and the parts cost $3-400.  It's also common to have failures of the climate control brain (the piece that shows the !!)

To actually test it you need an Autologic or T4 type system.  It's not scannable with a generic OBD II scanner