2005 nissan sentra se-r and the cabin air switch does not work

check to see if the air actuator is working on the heater unit . it's under the dash on the heater and have fun trying to find it as it can be anywhere. i'll send a generic pic along so you know what you are looking for.

Okay thanks for repling but i still have a question about the picture you sent. What part am I lookin for and how will I k is if it is working or not?

ok here is apic of yoru unit. this may be by the gas pedal. asyou can see in teh pic there is acable. all you need to do is to move the mode switch and watch if the cable is moving. if it isn't then the cable or switch is broken. if the cable is broken you'll need to replace it. if the cable moves then the door is broken and will have to be disassembled and repaired. I'm betting the cable is broken.