Animal (dead?) smell in air vents, Honda Accord '97 -- Urgent - Expert Advice most welcome

I have a Honda Accord '97 SE. When I turn on the air conditioner I get a very foul smell coming from the top air vents (not the bottom). Smells like a dead animal (mouse? - they have definitely been in the car, nesting and all), or their droppings/urine?

Took the car to the shop and they could find nothing in the blower (usual place for dead mice) and are now talking about having to take apart the whole dashboard to investigate. They can’t estimate how long this might take or how much this will cost.

They DID find that the airconditioner is no longer working and that needs replacing, which means a major $ outlay.

Living without air conditioning is not an option – NC summers, plus the AC has to stay on in winter to prevent windows from fogging up.

1. Any ideas about how to figure out where the smell is coming from, and/or how to get rid of it, that won’t cost a lot of $$$$$$?

2. Is there something I can check out before paying a mechanic to do that?

3. Any thoughts on how to successfully keep mice out of the car (we live in the woods). I’ve read this is a common problem for Hondas.


Mice usually come in through the outside air vent that is located under cowl. If you remove the cowling, you can put some 1/8" hardware cloth over it to keep them out. From there, they go down into the blower and maybe as far as the ac evaporator. They can’t go any further unless you switch to inside air. Then they can get anywhere in the car.

With the blower motor out, they should have been able to check the cavity before the evaporator for a dead mouse, that is the most likely place that it would be.

How did shop figure out that you ac didn’t work and you didn’t know?

Keith – Thank you for your input.

Some other questions: where is the cowl you mentioned? Would like to cover the air vent as you suggested.

I usually keep the air vents on “inside air” because I cannot tolerate the smells of exhaust et. al. which inevitably enter when the vents are open. But I will remember to switch them to open position when I park from now on.

They discovered that the AC was broken because I was not getting any cold air from the lower vents, and very little from the upper, and I asked them to check. They found a leak in the compressor, and said the fluid was going through several parts of it which it isn’t supposed to do, and it also needs a new receiver.

Is there a way I can get a diagram of how all this is put together (especially the air circulation system)? Also, is there a way I could personally take out the vent “shades”, the things that regulate where the air is sent, that is part of the dash?

Thanks in advance for taking the time to respond.

Normally the cowl (technically cowl cover) is that part between the base of the windshield and the hood, but on a 97 Accord, its the black piece under the hood at the base of the windshield.

On the drivers side, you can see through the vent holes in the cowl cover, the wiper motor is under this side. This lets the air into the cowl, the vent to the cabin is under the solid section on the passenger side. You have to remove the wipers, then the six plastic anchors with the phillips head in the center to remove the cover.

As for removing the doors in the vents, I wouldn’t do that. If you leave the vent on inside air all the time, then the mice should not have been able to get into the blower motor area, but there might be a dead mouse on top of the vent door, or a mouse nest on top of it and baby mouse urine or the smell of the dead mouse is getting down into the blower compartment. When they take out the blower motor, the need to open this vent door to see.

BTW, it doesn’t matter whether your on inside air or not, some outside air, with all it pollutants (and fresh oxygen) get in anyway, just not as fast.

The reason the entry to the blower compartment is under the solid side of the cowl cover is to keep rain out. Mice get to it by coming up the water drains at each side of the car just behind the front wheels. All the water coming down you windshield and onto the cowl cover, and sometimes in the cowl itself exits down those drains. The entrance to the blower motor chamber is through a raised vent, raised about a 1/2" above the floor of the cowl.

Does the odor resemble “wet dog?” Our son bought a “pre-owned” Ford Explorer "circa '99) which came with & retained that odor for over two years! He bought something to insert in a/c vents which eventually seemed to rid the vehicle of majority of that odor.

We had a similar ‘wet dog’ odor in our suburban (also broken a/c) which seemed to begin after I cleaned its carpeting. (BTW…neither of us ever owned dogs.)

Did the mechanic indicate malfunction in the a/c system?

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