05 subaru blows hot air on drivers side and cold air on pass when heat is turned on

Do you have dual climate control? The settings could be off or there is a fault in the system.

Check between radio console and passenger side plasticware for cable disconnected from heater door (get on your knees to see how it clips into swivel). How's the engine coolant temp gauge looking? If it threatens to overheat I'd check for blockage in either of the water hoses going back to the heater core (backflush if necessary). If you're convinced that there's proper circulation AND the cooling system is fully purged of air continue to drive. But if you have a high pressure internal head gasket breech you'll percolate hot air into the coolant hose which then settles at the high point in the heater box, resulting in cooler air at the upper vents...usually the right (pass) side first. But i hope it's not the latter, as at that point I'll recommend that you toss this dozen-year-old turbo as it's at the end of its useful life...regardless of mileage. Good luck.

FoR could be right...very clever. In Legs/OBs/GT dual auto- climate was bundled with LEATHER in LIMITED models only. I've yet to have one of these auto-climates fail. If you DO have this fancier auto-system I'd simply try swapping out the whole control panel with a salvaged one before chasing electrical or sensor problems, as it can get hairy in there.

Thanks for info guys but have standard model no dual climate. But what i forget to mention is that new thermo and head gaskets where replaced recently and all gauges now read in normal range.

Ta dah!! Christ, man.... Ask your wrenches to purge the cooling system...you've got air trapped in the heater core.