Jack1944

Gamalot: Same deal with my wife - a dead rat in the glovebox laying on top of the spiff leather Owner's Manual doesn't make one think luxury. We were set to buy a new 2020 RX350 (envious of Les's great red one), but now we are uncertain what to do. Searching on Google, other brands have the same problems. I do know that regardless of what we buy, I will be exploring the rodent pathways and screening them up right away, warranty or no warranty. (BTW, if you drop the plastic plate below the glovebox (no tools needed on my 2005), you may find quite a messy nesting area, since there is a blower sound reduction pad there, made of soft and comfy white batting . Like staying at the Ritz to a rodent, no doubt. Perhaps that is where your little visitor fell from. My batting had several date pits in it, since they even brought their own dinner back to their room, to eat in bed I guess.)

Thanks very much Les for looking at your 2020 and very clever of you to do with a piece of wire what I needed an endoscope to figure out. I wonder why, 15 years and many complaints later, Lexus still does not think it would be useful to screen off the fresh air ports they put through the firewall? Do they not understand that mice can chew through rubber, plastic, and even metal, given the time and opportunity? Here are some endoscope views of openings mice have made through the top of my blower housing, which is made of rather thick, hard plastic. 1247623912_blowerinputport.mp4

Results of colonoscopy on 2005 RX330. I bought an endoscope to try to understand how mice were getting into my heating system and into the cabin. The 8 attached photos explain what I think I learned. To summarize, rainwater runoff from the windshield is channeled on top of a cowling that empties into large rain drain shafts that run vertically to the ground behind the wheelwells. They are big enough that high flows of water (and leaves and waste and mice) can get into them. There are access points for mice behind the hood hinges, where rainwater enters as well. Previous suggestions to tape over these areas were on the right track, but the openings are irregularly shaped and hard to tape over. Unfortunately, there are large unscreened access holes beneath the cowling where the mice can easily get from the drain shafts into a large open trough where the wiper motor and linkage is mounted. On the passenger side of the cowling, an air grill is positioned just above where the blower fresh air intake port is located. This is a large 3 x 15 inch hole in the firewall. Extremely unfortunately, this entire large port is not screened off in any way from the wiper mounting trough. So mice can just step unimpeded onto the top of the blower and immediately be sitting on the air filter. Also, at least in my car, they had little trouble chewing through the white plastic blower housing and getting access into the cabin. They also chewed through the front of the filter tray. My solution (hopefully) was to fasten ¼ inch galvanized screen in front of the large firewall openings that lead to the top of the blower. After I did this, I continued to trap mice inside the car for a couple of days, since (I think) resident mice could not escape with the new screening in place. It has been about a week now that no new mice or droppings have been found in the car. Apparently the clever Lexus airflow layout is not unique to my car. In Youtube videos showing how to remove the wiper cowling from other Toyotas, you can see what looks like similar, unscreened openings through the firewall to the blower . I also see that owners of other makes of cars have resorted to metal screening solutions. I will post again to update the group on the success of my attempt to screen out rodents. (And if anyone has reason to take off their wiper cowling, I would be very interested if newer RX models still have unscreened access to the blower. It seems dumber than I can imagine, but I am not a luxury car engineer......)

The search for an entry path to the cabin continues. I tried to make a better diagram of the ducting following Les Lex's suggestions (see attached). When I run my RX330 heater, hot air comes out of the under-seat ducts (#18 in the diagram). I also found the cabin exhaust vents Les described - they are slits that are cleverly built into the rear shelf supports (the shelf for the screen that can block the view into the back storage area). Most importantly, I found that the upper lip of the cabin air filter tray has been nibbled away along most of its length, creating a 1/8 inch wide gap right above the glove box (see green dotted line in drawing). The plastic also is somewhat bendable, possibly creating enough space for mice to enter the cabin without chewing through the air filter. I ordered a replacement air filter tray and will try to mouse-proof it with metal strips. This could be how rodents get into the cabin, but it still does not explain how they get on top of the filter. I find large unbroken leaves, 1/2 inch date pits, nesting stuff - all sorts of crud that could not fit through any of the 1/8 inch air intake holes in the grills near the wipers. There must be a large unscreened pathway to the top of the filter.

I found a drawing of my blower housing at a parts store, but am not sure what ports go where. Can anyone comment on the tentative red labels I have put on this drawing? As a possible hint, the upper blower port appears triangular and is about the same shape and location as the outside air intake grill under the hood. I ordered a bore inspection camera and will attempt a colonoscopy on my A/C system to see just what is happening...

Hi RX400h - thanks for the link. I had seen this before. So far, I have not had wiring troubles, just a messy, smelly unwanted invasion of my beautiful RX330. Afraid to turn on the heater for fear of what odors may come out........

In 13 years of having this problem, they have never eaten through the cabin air filter. There is tons of waste and nesting material on top of it, but they have never chewed it. And yet they die in the glove box, !Removed! all through the cabin, leave dates on the floor, have big parties every night it seems. I wonder if the airflow layout is different in my older RX330 (2005) - I don't see the opening that you described as the "rear exhaust vent". Is that the trapezoidal grill that you showed a photo of in an earlier post? Is it in the floor in the back of the vehicle somewhere? I dont seem to have any of those.... But then I am a blind old man, losing many of his faculties - it may be right there in front of my face. thanks for your continuing help. Tonight I have trail cams focused on the engine compartment - film at 11.

Yes, we have lots of rodents outside, and also have been storing 500 lbs of goose food in the garage, which has become a big self-serve mouse buffet . We are moving all feed storage elsewhere, but have had mice and rats in the RX330 since long before the feed storage. I'm sorry I wasn't more clear about the "air vents" I was referring to - see photos. The 11/64 square holes are in the air intake grills under the hood in the engine compartment, which some people had mentioned as a possible entry point. I can't see how that could be the problem. Other people have mentioned the holes where the hood hinges are located - they suggest taping these holes (see red tape in photo), but those holes have drains that route rainwater behind the wheel well and no grills at all, something I can't imagine Lexus would use as an air intake route. The in-cabin vents I was referring to in my 2005 RX330 are the under-the-front-seats ducts that blow A/C or heater air onto the feet of rear passengers (see photo). They are nearly 1/2 inch tall x 8 inches wide, with no grills. I am surmising that mice somehow find their way into the cabin, and then find their way into the heating system through these floor ducts. They end up on top of the cabin air filter, where they make nests and quite a mess. That access route is all a guess on my part, but I will keep using my trail cam to try to figure this out. (Also see photo of a sheet metal car corral solution that worked for someone in a rural environment.)

The air grill holes in my RX330 are square, 11/64 inch. Still trying to figure out how to block mice from accessing the cabin. Last night I used a field cam on the garage floor to learn that they come and go quite easily, by jumping up on the wheel rim, then up onto the suspension A-frame, then into the engine compartment (see video). Next step is to try to trace the agile little monsters and find where they enter the cabin. Also learned that leaving garage lights on at night, moth balls, PVC glue odor, and security lights do not affect them. They outsmart most traps except glue plates. But trapping and removing them (8 so far) is not the solution as long as they have such an easy way of re-entering. Lexus.mp4

Have had this exact problem for many years with my 2005 RX330. Mice and even rats can get into the cabin air system. They even bring date pits (from our trees) for their food stores. I have followed all the comments here for years and no one has ever posted exactly how they can possibly enter the cabin. In 60 years of owning many models of cars, I have never had this problem with other models. So discouraging to hear that newer RX models STILL have the same problem. They are not coming through the 1/8 inch holes in the air intake, or open windows, etc. My guess is that there must be a hole in the firewall or steering wheel shaft or somewhere so they get in the cabin. After that, they could crawl into the floor heater vents (no grill mesh on those) under the front seats and end up on top of the cabin air filter. I have trapped 3 so far this time. Problem has been ongoing since before gluetraps were invented, and once again, ONLY IN OUR RX330. No more Lexus for us. Shameful.