My 2007 Lexus ES350 (105k miles) has the AC putting out warm air to the driver side while cool comes out the passenger side. The car is equipped with a Dual Zone capability. But this is happening when dual zone is off and the unit is set at "LO" or the coldest setting.
I thought maybe a system recharge is in order but one side is very cold. Maybe a fuse/relay/rubber pressure tube?