AC/Heat making a cranking whirring sound?

Hey everyone! I just bought my 2006 sr5 V6 tundra a few days ago, super stoked. Im not a car person, but im trying to be so the last few day i been researching the hell out this truck! There are a few issues with it but the thing that I need taken care of first is the smell. It's bad guys, the last owner definitely had dogs but the thing just smells dank and kinda cheese. This makes me think the problem is connected to the AC somehow I just don't know if it's the condensate drainage tube being clogged or if it's the evaporator core. Any help or advice is greatly appreciated!
Edit: the last owners did an engine replacement through Toyota about 70,000 miles ago

 

Could be your carpets and or seats.

 

Stick a ozone machine in there for a day with the windows up

 

If it's your AC drain if you look under the hood passenger side you'll see a small hose coming out of the firewall. That's the drain hose. Could try to clean it out with something if it's not draining. Cowl clips on the passenger side like to leak too. These are what the screws that hold down the cowl (black piece under the windshield on the outside) thread into. Only 1 or 2 clips matter. Look under the definitive leak thread for more.
https://www.tundras.com/threads/definitive-2000-2006-cab-area-rain-water-leak-thread.70464/

As for the smell you already have, other than replacing carpet and everything else if necessary could try a carpet shampooer or the ozone generator others mentioned.

 

Remove blower motor and clean it.
Remove resistor near blower to clean out cooling coils.
Use a UV light and some yellow glasses to look at the carpet and seats for hidden pet stains.

 

Official welcome.

 

Thanks everyone for the helpful tips and warm welcome! I got a day off this weekend so I'll let you guys know what I find

 

Search all nooks and crannies....

My Tundra and the rats that almost killed me | Toyota Tundra Forum (tundras.com)

 

I'm going to guess that your truck probably has any of the number of leaks which would cause mildew growth in the vehicle and make it smell like ass. Spores would get in the A/C vents and you'd have an uphill battle on your hands.

Check this thread: https://www.tundras.com/threads/definitive-2000-2006-cab-area-rain-water-leak-thread.70464/

For probably the most common leak in our trucks, search the thread for 'Cowl Fasteners', then watch the video at the bottom.

3rd brake light is another big one.