have dual air,hot on one side and cold on the other

Hello i have seem this problem serveral times and the blend door actuator is sticking and may need to be replaced.You should try and reset the blend doors by placing the dr.side at full cold and the pass.side at full hot and turn the igntion key to the on position not starting the engine for about 1min.Then turn the key off and then start the engine and slowly move both temp.switches to the middle reading and if this dose not reset the blend doors you will need a system diagnostic.HAVE A BLESS DAY from DR.RECO.