My 2007 Toyota Corolla had a mouse build a home ontop of the fresh air intake filter. I removed the mouse house, used high pressure air, vacuums, lysol, etc. to clean it up as best I could, and replaced the filter (twice now). The problem - I still have a funky smell when I run the AC or Defrost.

I have tried more lysol blasts on high heat, cleaning, etc. No luck. The odd part is that if I run heat or fresh air - no smell. It's only when the compressor is on that this smell comes out. My guess is bacteria, another mouse nest somewhere else, or another filter I don't know about?

Any ideas on how to clean out or get rid of a stale, almost dead mouse smell, everytime I run the AC / Defrost?? Please?.... it's 80 and humid here in NH today - it's going to be a long ride home without running AC!

Any thoughts on this? Are there other air filters, drains, etc.. to get rid of this smell?
I already sold 1 car due to the same reason!

Real fix - get rid of the mice in the garage!!!

Can anyone help explain how the AC works? How does the cold air get into the car ducts? There had to be more mouse next or something that is causing the smell. Anything?

The A/C system is completely enclosed. There is no way for odor to get into the a/c lines, so that's out. You probably need a deeper clean, which will involve disassembly of your blower assembly and evaporator box under the dash. This involves disconnecting two of your a/c lines running through the firewall. You will need to recharge the system once you are through. Buy a service manual from your local parts store (money well spent).

1. Disconnect negative on battery. Failure to do so could result in blowing your airbags.

2. Disconnect the two a/c lines (under the hood) running through your passenger-sid firewall.

3. Remove glove box and any panels necessary to gain access to the blower box and evaporator

4. Remove/disconnect all electrical connections mounted on your target areas.

5. Remove the nuts/bolts shown in the manual (usually nuts holding the boxes to the fire wall, bolts tying the two boxes to eachother).

6. Pull the boxes out from under the dash.

7. Remove fan motor clean by hand (DO NOT SUBMERGE MOTOR IN WATER). Clean fan motor box with soap and water.

8. Remove outer case from evaportator (splits in half). CAUTION: EVAPORATOR FINS ARE EXTREMELY FRAGILE. DAMAGE WILL RESULT IN LOSS OF FREON CHARGE.

9. Cap/Plug all a/c orifices. Failure to do so can result in moisure build-up in your a/c system.

10. Clean evaporator and evap box with soap and water.

11. Check drain tube for blockage (could be done first, but you would probably still need to do a deep clean to the system because of the mold/debris backup). Make sure to check the cabin side of the tube and the side coming out of the firewall (under the car). Run a small screw driver in to gently dislodge anything that may have built up.

12. Reassemble in reverse order.

13. Add new R134 freon, usually about 2 cans, but check your manual to be sure.


That ought to take care of your smell, unless your friend got up in the actual vents themselves...in which case, you will need to disassemble the dash, remove the ducts and hose them out, too.


Good luck, let me know how it goes.

Rob