I have a 91 ls400 with some air issues. The air blows fine but whatever the temperature is outside is what blows through the vents. I survived the summer but i don't do winter. is this a core problem or just a valve or thermometer?

Thanks

 

what have you done???
is your AC working/running?
is it full of freon?
will your system change from vents to floor??

give us some clues, not just a statement like my car wont start, what's wrong with it???

 

Sounds like it needs to be charged with freon but if you have leaks in the system it could get expensive.