Willzale2002Z71

Hello I am a new Tahoe owner (2002 Tahoe 5.3, Z71) when I bought it it was abandoned for a couple of years, mice and snakes made it their home. That being said after cleaning and replacing the cabin air filter, the air and heat just reeks of mouse crap. My question is where should I go from here? The defrost doesn’t work because (I think) it’s clogged with stuff but I don’t know how difficult it would be to take all that out. Should I spend a day trying to take all that out? It doesn’t stink as bad on the face vents but still smells.

jfmorris

I hate to say this, but odds are that they were nesting inside the HVAC module up under the dash, and that it is full of mouse poop, urine and nesting material. This is where the heater core, blower, flaps that control where air goes, all that is. The big black enclosure under the dash, extending from around the gas pedal over to under the glovebox.

Here's an exploded diagram of all the stuff in there:

https://charm.li/Chevy%20Truck/2002/...0Conditioning/

Odds are stuff is up there on top of stuff like the heater core, but I would see if I could drop that lower HVAC module case (#13 on the diagram) and clean it out best I could. I would start by removing the blower, and confirming there is crap inside the housing if you can, but odds are that the housing and all vents really need to be removed and cleaned. Unfortunately, fully removing it means removing the entire dash of the vehicle, which is very time consuming and involved.

Rednucleus

Also, mouse urine/feces can carry Hanta virus, don't want to be aerosolizing that in to your cabin. Think you need to totally tear down the hvac ducting and clean/disinfect.

Willzale2002Z71

Ok yeah I will definitely be doing something about it then… I have MAJOR allergies and can’t be using contaminated air. (I haven’t been using it). When I took out the cabin filter, I did look with a flashlight at the evaporator core (i think) and it was spotless. However I’ve changed the cabin filter 2 times and each time they were full of mouse droppings and nest material. But from what I could barely see I didn’t see anything on the core side.

jfmorris

I would imagine they came in from the vents, or from outside the vehicle, and nested on top of the evaporator, farther up inside the box. Stuff is probably getting dislodged and falling down to the cabin air filter area during operation.

If this is not your daily driver, I would find a GOOD Youtube video on the teardown of this for a GMT800 vehicle (any truck or SUV in the 1999-2006 time frame) and put in the 20 hours or so labor it will take, taking your time with it. As I mentioned, the entire dash pretty much has to be taken apart and removed to get all the ducts and the entire air handler out. Soak and clean it good, and I imagine assembly will go faster.

Here's a video I found in a quick search. 15 minutes long, and time lapse of course, as it takes hours to do. This is specific to the heater core, which is at the TOP end of the assembly up under the dash, but should help give you an idea of what all is involved.


By sure to disable any security features, and then disconnect the battery as he says, as otherwise you could blow an air bag accidentally. I say to disable any anti-theft system as I think those can cause issues after an extended time with the battery disconnected. Neither of my trucks have that kind of system.

Willzale2002Z71

Yeah unfortunately it is my daily, and I’m still in school. The ac isn’t to bad cause I’ll just roll the windows down but the heat is what I’ll be missing if i don’t clean it. Thank you for proving me the video and for your replies! I will update you when I get time to do this.