[ajan246]

Hey Guys,
I’ve benefited so much from this site I decided I’d give something back. Even though its October in Texas it is still hot and humid. I’ve been running my AC every day and started to notice a funky smell like I left a gym bag in the car. That same day I went to grab a notebook that had fallen to the passenger side floorboard and it was soaking wet. I did some research and out that this was most likely caused by a clogged AC drain. I did some searching online and found some info on the older model Tundras and a black hose on the passenger side underbody that you can clear out. But my 2015 SR5 TSS truck did not have that. So, I tracked the small amount of water that was dripping back up to above the transmission area. The drain you need to find is located directly above the transmission on the center of the underside of the firewall. There is a small rectangular piece of plastic it’s about 2”x2” and on that piece is a small half-moon shaped hole where the water was dripping out of. I tried to stick weed-wacker string, wire, zip ties etc up in there to clear out the clog but it did not work. What worked was an air compressor with an air sprayer and a sharp pointed tip. I was able to get the sharp point of the air sprayer into the small opening and blow out the clog. About 2 cups of water came rushing out when the clog broke free. I fired up the truck and let the AC run for a while and no more leaks! Now I’m just drying out the carpet and trying to get rid of the smell. I’ve attached some photos below for anyone who may run into this.


Here is where the water is going to drip from on the passenger side floorboard. It will soak the entire carpet really quick.

Here is the drain location. It is located directly above the transmission. Dead center on the underside of the firewall. This is what you're looking for.

I tried poking a wire into the hole to clear it out but that did not work.

Here is the tool I used to spray out the clog with compressed air. I bought it at harbor freight.

This is the amount of water that rushed out when the clog broke free.

If you have any questions please let me know. I have videos and more photos in case I forget about this the next time it happens. Good Luck!

 

[SilverSwagger]

So where did you put the air nozzle? Up into the hole?

 

[Mickleford]

Good info! Thanks for sharing!

 

[ajan246]

So where did you put the air nozzle? Up into the hole?

Yes exactly. See the photo where I tried clearing it with the copper wire? Stick the air nozzle in that exact spot and blast it out.

 

[Big Shasta]

Yes exactly. See the photo where I tried clearing it with the copper wire? Stick the air nozzle in that exact spot and blast it out.

Glad it worked but didn't you really blast it "IN"? Wonder if there is any way to apply vacuum?

 

[OldGuy43]

Glad it worked but didn't you really blast it "IN"? Wonder if there is any way to apply vacuum?

There are probably only as many ways to apply vaccuum as there are "driveway geniuses" with duct tape and hose. Getting it to be effective?...now, that is another matter. The slime "blasted" in will likely die off and desiccate once the AC stops being used, and then the cycle will begin anew next Spring.

 

[ajan246]

Glad it worked but didn't you really blast it "IN"? Wonder if there is any way to apply vacuum?

It's very possible...however when the clog breaks loose water comes rushing out. I imagine some of the slime and gunk was flushed out when things opened up.

 

[Thomasbus337]

Does that drain have a plastic or rubber flapped opening? I tried to use a can of A/C condenser cleaner but couldn't get the small plastic tubing to insert anywhere in that area.

 

[ajan246]

Does that drain have a plastic or rubber flapped opening? I tried to use a can of A/C condenser cleaner but couldn't get the small plastic tubing to insert anywhere in that area.

No, it looks like it would but its all hard plastic. The only opening is that small half moon shape from the photos above.

 

[Majthom]

Thanks for this. I'm having the same problem, leaking on driver's side and passenger floorboards. Coming from under dash center. I've sprayed air up into the drain as described here twice now. It wasnt dripping out before but now it is. However, it's still leaking inside the cab. If I run the ac for 5 mins and then shut off the truck, water will puddle on the ground as it should. But still leaks from under dash. We've had no rain for a couple weeks, so it's definitely coming from the AC. Where/what else should I check. Thanks guys.

 

[ajan246]

If you haven't had a gush of water come flowing out like you popped a water balloon.. my guess is that you haven't broken up the clog... try a thin wire to poke around first and then see if you can get a long thin air compressor extension to shove up there. Also, make sure your compressor has as much PSI loaded up as possible! good luck!

 

[Jonl]

Thanks for this thread! I had no idea where the drain was on the Tundra.
The drain is very narrow. I was able to trim a piece of heavy duty plastic box strapping to clear it out. A zip tie would also fit. If it does it again I’ll consider removing the whole cover and maybe flushing it out.

 

[edicted]

Thanks for the post.

Can anyone point to where this drain port is located?

I've looked under the hood, under the truck, behind the passenger side tire well and no luck.

 

[Jonl]

It’s above the transmission on the centerline of the transmission tunnel. Look for two silver nuts holding the black plastic drain plug. The drain slot is on the engine side of the plug.
Underneath the truck.

 

[edicted]

It’s above the transmission on the centerline of the transmission tunnel. Look for two silver nuts holding the black plastic drain plug. The drain slot is on the engine side of the plug.
Underneath the truck.

Thank you. I'll check it out. I was under there yesterday and could not locate it. I'll look where you described.

Thanks again.

 

[Geezer]

I had a problem with water on the floor in my wife's Highlander. I used weed whacker line to clear the AC drain and sunroof drains. Compressed air is a good idea unless the clog is above the hose itself in which case you could pop the hose off of it's fitting at the end that is not accessible.

 

[edicted]

Adding to ajan246's original post.

After some help from Jonl I found the drain port (not tube) by looking at the top of the transmission bell housing from the driver's side.

I went under the truck feet first. If you go head first you won't see it. You have to be a bit of contortionist to see the port and there's no easy way to access it. I ended up shoving my right arm up in between the front driveshaft and the frame with the air nozzle in hand and got the nozzle tip as close as I could to the port.

After a few blasts of air, I got soaked. There must have been about a half a gallon of water in there.

Afterwards, I ran the A/C on fresh air until it was dripping out normally. Then ran it on recirculate and ensured no more water was coming into the passenger side foot well and saw lots of water dripping under the truck.

I also ended up setting up a small desk fan and pulled one of the floor drain plugs to allow for the water to drain and for the carpet and padding to dry out.

Hope this helps someone else going forward.

 

[dogsridewith]

Same on a 2007? (first year of gen 2) Prepping for oil drain, went under w/ engine running and A/C likely on. Water was dripping from the driver side catalytic converter shield...is that normal if the HVAC box drain is in normal place and nothing is clogged?

 

[2010tundracbc]

Thank you for sharing!
I have weather tech mats in my truck and by the time I figured out o have water inside it was all over, both sides in front and even by the back seat.
The drain outlet is almost impossible to get to, no idea how you were able to actually take pictures of it.
Once I got in there with the compressor nozzle a bucket of water came out.
Probably the stealership would quote me for a engine removal to clean the drain

 

[Cliffcon]

Same on a 2007? (first year of gen 2) Prepping for oil drain, went under w/ engine running and A/C likely on. Water was dripping from the driver side catalytic converter shield...is that normal if the HVAC box drain is in normal place and nothing is clogged?

That water is coming from the catalytic converter. It is normal. A catalytic converter works by converting carbon monoxide into carbon dioxide and water. That is why you will have water come from you exhaust tip usually when first start up in the morning.