When I use my A/C for a long period of time. Say the 30 minute drive home from work. I will stop at a store for say 15+ minutes. Get back in the car and use the A/C. It will smell in cat **** (ammonia smell). Any idea why this is happening?

 

Read this article. I have the same problem on a brand new 2005 bought in April! I used a can of Wynn's air fresh. Works so far, we'll see how it goes over the next few days.
A/C smell

And there's this thread...http://forums.maxima.org/showthread.php?t=406568

 

I did the Lysol thing... it worked for me.

First: Turn the a/c on the recirculation mode. Spray into the air inlet inside the car.
Second: Turn the a/c on the vent mode. Spray into the air inlet outside the car.

Be sure to use a scent that you don't mind having in your car for a few days. I couldn't wait for the lysol smell to go away and I could smell the leather again...

 

Where is the inlet your talking about?