Why does my air conditioner smell like mold and mildew...

I may have found the source! I too had a bad smell - especially noticeable after the vehicle had become wet. Open your doors and check the spot on the jamb at the very bottom.juzt behind the mudflaps. Mine was full of leaves and twigs on both sides. I used a piece of nylon strapping material with a bunch of snags notched into it to help drag the crap out. I had to really flap it around in there and snag the leaves to get it all. I'm almost 100% sure this was the problem.

 

Frigi-Clean on the evaporator coils and Frigi-Fresh in the ducts (after a cabin air filter change) can help with this as well.

 

I drive with the AC on and all the windows rolled down

 

Truck has not smelled bad at all this summer and I have not done anything different.

 

This seems to be a chick thing. All women like the recirc for some reason. Every one I’ve known always runs on recirc. I can’t handle it for lack of oxygen sake. Plus, the windows get dirty and foggy quicky from recirc.

 

Me too! I love that double sensational feeling.

 

Hormones change over time.

 

I recirc my a/c, but I like to dutch oven myself.

 

I would have say a cloged drain to, see if it is leaving a puddle of water under the truck on a humid day.

 

I have had this problem on multiple vehicles (Houston and San Antonio). It was really bad in my Lexus SC, had to use the Toyota evaporator refresh kit every year. Also had the problem in 2013 Tahoe and BMW 5 series. Both issues were from mildew on the evap coils, usually shutting down the vehicle with cold coils and the moisture would never fully evaporate. Never had an issue with older tahoe, broncos, f150s but figure it has something to do with how well sealed the a/c system is. My solution was first to clean the coils really well. I used evap coil cleaner and even experimented with a little Isopro. Alcohol in distilled water and found that worked the best but only used it with battery disconnected and blew out the vents manually with small fan. Evap coil cleaner was the easiest. Once cleaned up I found shutting off my compressor about a mile before I get home to equalize the evap/cond coil and leave the blower on to remove most of the moisture kept things fresh, no longer have problems with dirty sock syndrome. I practice the same routine on my Tundra now as preventive measure.

 

Yeah, I just turn the AC off, and the blower up for the last 5 minutes or so we're in the car. I havent had any problems yet, but it IS only a year old. I'm in houston, so humidity is an issue...

 

I live less than a mile from the gulf and I have never had this problem with any vehicle.

 

Guys, you have to do the above on every car nowadays. I have other cars and if i don't do the above it will start smelling.

It is standard AC operation. In your own home, after the thermostat has been satisfied, the furnace or air handler will run the blower fan about 90 secs to help in drying out the coil, so there's not much mold buildup. Same theory here, but you'll have to do it on your own. Turn off AC, open the fresh air and put blower on highest for at least 2 mins before you shut it down.

 

Yeah, this is so stupid. They need to make the fan run on it's own after turning off the ac. Even after the truck is turned off. Kinda like the old Turbo Timers. Having to turn off your AC a few minutes before arriving at a destination is just ridiculous when it's 100* outside.

 

Seems like the blower running alone wouldnt draw a ton of power either.... I like it.

 

Ford will probably come up with it first.

 

I agree. Or like the VW's where the fan continues to cool the motor although has been shut off.

 

yep. And then it will short, catch fire, but the fan will still be running so those flames can be fanned inorder to do the most damage. Dont want you to beable to repair it, gotta rebuy new!

 

If that doesn't happen, it will just keep running until the battery dies.

 

Sure. Go with the most probable issue... no imagination.. lol

 

LOL. Yours was good. We just need a back up failure to your failure. It is a Ford afterall.

 

Get a can of lysol spray. Roll all the windows down. Make sure trucks on fresh air NOT recirculate. Spray lysol into vent by front windshield.

 

When the system is set on heat does the heated air pass through the refrigerant coil? Or is cool air drawn through it? Seems like the heater would burn out any mildew as hot as it gets.

 

GM has a feature built in that can be turned on called "After Blow." It turns on the blower for a set amount of time when the car is off if certain conditions are met, such as battery state, length of time a/c run, etc... You have to ask the dealer to turn the feature on though, go figure.

 

After blow

 

At least they keep it simple. If it was German-engineered it'd be something like Verfahren zur Reduzierung der bakteriellen Luftmenge.

 

Same issue.
When I took my truck in at 4 months for something else the dealer wanted to run some kind of foam through the system to get rid of the mildew smell.

 

Turn your ac off at least a minute or two before you turn the truck off, or spray your vents together with the ones by the wipers with whatever odor destroyer spray you like, let it circulate with the AC on

 

Years ago, I owned a Pontiac that had a horrible A/C odor. The dealer installed an Air Conditioning Blower Motor Delay Module Kit, similar to this one:

$103 ACDelco GM Original Equipment 15-5876 Heating and Air Conditioning Blower Motor Delay Module Kit

https://www.amazon.com/ACDelco-15-5...e=UTF8&qid=1532736343&sr=1-1&keywords=15-5876 “…allows the HVAC blower to operate for a brief period after the vehicle is turned off. This helps to dry the evaporator core to reduce biological growth and odors.” It solved my problem. Wish Toyota had one available.

I also had a habit of using A/C recirculation mode on my ’05 Tundra to avoid smelling / breathing exhaust fumes during my bumper to bumper work commute. Once the A/C odor started, no amount of Frigi Fresh would cure it for very long. I finally adopted the habit of turning off the A/C 5 minutes before arriving at my destination and disabling recirculate mode. It helped a lot, but once in a while I would forget, and wow, the funk would return immediately with vengeance.

I’m not taking chances with my ’18 Tundra. A/C gets turned off, recirculate off, and blower motor turned to high 4-5 minutes before my destination.

 

Guys I’ll look and see if I can find it but I can’t promise anything. I remember in the mid-90’s Volvo Europe was having us install a relay that would engage about 5-10 min after the vehicle was shut off.

It was a really simple install maybe I can still find a schematic or the part number of the relay(after blow kit)