We bought our 2017 Expedition EL Limited about 10 months ago. Had 59,000 miles, now has 69,000. About 2 days it developed a bad smell. Moldy or mildew smell. Its around all the time, maybe a little worse when the AC is on. I spent hours detailing it. Cleaned out everything, vacuumed everything, wiped every surface, cleaned all the leather. The smell is still there. It has weather tech liners and I didn't see any evidence of a major spill. Anyone had this problem? Is the AC system the culprit?

 

I'm not a mechanic, but my first thought was that the smell might be coming from an old cabin air filter. When was the last time it was changed out?

 

From what I can tell it doesn't have a cabin air filter. Expedition didn't get one until the 2018 refresh.

 

This will fix the issue.

 

A/C evaporator drain clogged? Does it drip condensation under the passenger floorboard area when parked after driving with the a/c on for a while, it might not if you live somewhere with a dry climate.

 

Friend of mine, who lives about 1500 miles from us called the other day. She has a 2018 Expedition Max with 70 k miles on it. The A/C fan quit and she took it to the dealer. The dealer found that there was moisture and mold under the passenger side carpeting and kick panel, and the passenger side wiring channel under the passenger side door sill was full of water. The dealer thinks that the sun roof drain hose was improperly installed at the factory and that the vehicle needs to have the wiring harness replaced. The wiring harness is on national back order and could take 3 to 4 months before one is available. Between the price of the wiring harness and the hours to install, the dealer estimates it will cost her between $10,000 and $12,000 to repair.

I hope this is not your culprit.

 

Rear drain was plugged. Kool-it heater core ac condenser cleaner worked great. Smells like new again, until a kid puked in it.

 

I've got an ozone generator that I use for all manner of odor remover. Moldy, musty, stale, food, farm, etc. If it's got an odor, the ozone will knock it out in short order. They're about $200 and well worth the money!