Bad Smell Coming From Air Vents

[ElectrifyingMe25]

Has anyone had to solve the problem of an odor coming from your air vents?

The odor smells like it may be from mouse nest/urine, but maybe not. That smell is the closest odor I can relate it to. It seemed to start after I used the A/C the other day. The smell is not there if I don't run my vent fan. The smell seemed to start up almost overnight or within a couple of days, according to my son's nose.

I checked the cabin filter under the glovebox and it was clean and didn't smell.

I'm hoping one of you guys knows how to pinpoint the source of the smell. Have any of you had to solve a problem like this on your F-150s.

Thanks for your help.

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[bluey2025]

Your not the only one. I bought my 25' XLT in August. I live in SW Florida so AC is almost always on and cranked with the recirc on. I noticed a strong smell like a cross between mildew and cat urine. Best thing I've found is to turn the AC off and let the blower run for roughly a minute before parking with the recirculate button off. Doing this dries out the evaporator and uses fresh air to do so.

 

[ElectrifyingMe25]

Your not the only one. I bought my 25' XLT in August. I live in SW Florida so AC is almost always on and cranked with the recirc on. I noticed a strong smell like a cross between mildew and cat urine. Best thing I've found is to turn the AC off and let the blower run for roughly a minute before parking with the recirculate button off. Doing this dries out the evaporator and uses fresh air to do so.

Thanks... I will try what you suggested.

Does anyone know of an aluminum and duct safe way to flush the evaporator coils? Is there an easy way to get to the evoporator coil? I am assuming the intake side is just above the cabin filter. My cabin filter didn't smell. So I guess the source of the stink is below the filter. I also noticed the blower fan blade resides just below the filter. So my guess is the evaporator coil is just beyond the fan discharge.

Isn't it amazing how many problems are thrown our way each day..... as if I didn't have 100 other issues I'm dealing with.

 

[CD4TNF]

Common problem. Plenty of threads here for tips.


My solution was to use this antibacterial surface cleaner. Poured some down all the outside air vents until it ran out the drain holes. Ventilated the inside of the cabin with windows down for 15-30 mins to evaporate the stuff. I haven't had problems since.


https://cleansmarthome.com/collections/household-disinfecting


My hypothesis is dirt and organic matter fall into the air intakes and collects by the drain where it rots. Kinda like the drain holes on the window shield collecting crud. The antibacterial solution kills off the stinky bacteria.


If you're looking at evaporator cool cleaning, I've been pondering using HVAC evaporator coil cleaners to clean the Lightning's coils. If you and I are talking about the same thing, the evaporator coils are easily seen from the front vents. My plan was to take some of that foamy spray can evaporator coil cleaner and spray it up onto the evaporator coil.

 

[Tired Lizard]

Lightning Blower, Evap Coil, Heater Coil - HVAC system in RHD Ford F-150 Lightning Explained
Looks like a mirror of our LHD. Looks easy to get some kind of buildup.

LHD Evap Coil

 

[ElectrifyingMe25]

Lightning Blower, Evap Coil, Heater Coil - HVAC system in RHD Ford F-150 Lightning Explained
Looks like a mirror of our LHD. Looks easy to get some kind of buildup.

LHD Evap Coil

You have helped me understand the nature of the beast. Great information and great YouTube video that explains in detail how the HVAC works in a Lightning.

I tried to use a borescope to see the evaporator through the filter slot and squirrel-cage fan, but the tolerances were too tight. The blend doors get in the way wen you try to go through the dash vents. I guess I could turn on the A/C, and maybe get through the blend doors. I don't want to get my borescope hung.

I'm going to do a little more research before I do more.

Thanks for your help. Guys like you make this fourm so helpful.

 

[FnSUp]

For what it's worth, I have this issue, but the smell is due to a leaking sunroof. I did all the AC/intake/coil/etc cleaning that I found in these forums and it didn't take away the smell.

 

[chl]

Has anyone had to solve the problem of an odor coming from your air vents?

The odor smells like it may be from mouse nest/urine, but maybe not. That smell is the closest odor I can relate it to. It seemed to start after I used the A/C the other day. The smell is not there if I don't run my vent fan. The smell seemed to start up almost overnight or within a couple of days, according to my son's nose.

I checked the cabin filter under the glovebox and it was clean and didn't smell.

I'm hoping one of you guys knows how to pinpoint the source of the smell. Have any of you had to solve a problem like this on your F-150s.

Thanks for your help.

I had that problem one summer when it was very hot, over 100F, I parked in a hot asphalt parking lot with the truck turned off, probably over 120F there, shopped for 1/2 hour or so, then came back and started the AC set on MAX AC.

It blew bad smelling hot air so I turned it off.

I believe it was vaporized coolant, maybe from a compressor/fan seal or other seal that leaked because the system was overloaded from the the high temps. It smelled like coolant to me.

After I got home and waited with the truck parked in the shade, then turned on the MAX AC again, no smell and nice cool air.

Now I leave the AC on when I got shopping in the summer and have not experienced that problem again.

I'm going to look at that YouTube video and see if it helps explain my one-time event.

I remember there was at least one other owner that had a similar incident - pretty sure it was in the summer of 2024.

 

[Tom M]

Has anyone had to solve the problem of an odor coming from your air vents?

The odor smells like it may be from mouse nest/urine, but maybe not. That smell is the closest odor I can relate it to. It seemed to start after I used the A/C the other day. The smell is not there if I don't run my vent fan. The smell seemed to start up almost overnight or within a couple of days, according to my son's nose.

I checked the cabin filter under the glovebox and it was clean and didn't smell.

I'm hoping one of you guys knows how to pinpoint the source of the smell. Have any of you had to solve a problem like this on your F-150s.

Thanks for your help.

I live in a humid climate and had a similar problem. The condensation from the air conditioning drips across a foam seal that is on the passenger side firewall. Try this: https://static.nhtsa.gov/odi/tsbs/2019/MC-10168762-0001.pdf

 

[bc1]

I had that problem one summer when it was very hot, over 100F, I parked in a hot asphalt parking lot with the truck turned off, probably over 120F there, shopped for 1/2 hour or so, then came back and started the AC set on MAX AC.

It blew bad smelling hot air so I turned it off.

I believe it was vaporized coolant, maybe from a compressor/fan seal or other seal that leaked because the system was overloaded from the the high temps. It smelled like coolant to me.

After I got home and waited with the truck parked in the shade, then turned on the MAX AC again, no smell and nice cool air.

Now I leave the AC on when I got shopping in the summer and have not experienced that problem again.

I'm going to look at that YouTube video and see if it helps explain my one-time event.

I remember there was at least one other owner that had a similar incident - pretty sure it was in the summer of 2024.

Chris, on Max AC it is circulating inside air as you probably know. Maybe it was the smell of your own BO after the half hour shopping trip? Sorry I couldn't resist the joke. Hope you are doing well.

 

[ElectrifyingMe25]

Chris, on Max AC it is circulating inside air as you probably know. Maybe it was the smell of your own BO after the half hour shopping trip? Sorry I couldn't resist the joke. Hope you are doing well.

It's more likely the results of your stinking joke radiating from your post.

 

[chl]

Chris, on Max AC it is circulating inside air as you probably know. Maybe it was the smell of your own BO after the half hour shopping trip? Sorry I couldn't resist the joke. Hope you are doing well.

Ha, the store had good AC so I was not sweating as I entered the truck...definitely a chemical smell like a coolant. (My wife always lets me know when my manly smells become noticeable, and I got no feedback that day. )

The truck was young (about 7 or 8 months ownership at the time) and it has no carpet to get wet and moldy from no sunroof, no pets have been in it, no critters hiding in the AC vents as far as I could tell either.

Leaving the truck running on hot days is not something I was accustomed to doing with ICE vehicles, or the 2012 Leaf with it's limited battery and range (24kWh and 100 miles if you drive carefully), but with the Lightning, it's now SOP.

 

[chl]

It's more likely the results of your stinking joke radiating from your post.

These days we need all the humor we can get to distract from reality, so let 'er rip!

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