Musty Smell when I turn on Heater

[Charles M]

I have a 2017 Ford Expedition Limited.

When I turn on the Heater there is a musty smell coming from I believe the Passenger side. Was never like this till about 3 weeks ago. I searched the forums here but could not find a solution.

Any Ideas where to look or what to do?

 

[99WhiteC5Coupe]

I have a 2017 Ford Expedition Limited.

When I turn on the Heater there is a musty smell coming from I believe the Passenger side. Was never like this till about 3 weeks ago. I searched the forums here but could not find a solution.

Any Ideas where to look or what to do?

Several thoughts:

Water leak which causes mold / mildew in the carpet (under any mats) - causing the smell?

Leaves and debris in the air inlet cowl location, causing the smell?

Snow or rain water on the mats (caused by passengers), which has wicked into the carpet and pad?

A dead rodent in the air inlet cowl area, or in the blower motor cage or duct, causing the smell?

The front HVAX blower motor can be removed from under the right (passenger) side of dash by removing connector and screws, pulling back the carpet and pad, and lowering the assembly. You could then examine the blower cage and ductwork (using a mirror if necessary).

Have you checked under the hood to determine if anything has built a nest there, causing the smell?

 

[jimz]

I had hose to rear wiper sprayer separate. As the hose enters through the firewall there is a butt to butt connector. That hose dumped cleaning fluid onto carper. Simple to remove plastic trim, reconnect connector (close to passengers toes) and no more problems.

 

[inmanlanier]

Check your condensate drain line from the AC. Each evaporator coil (the heat exchanger that makes the air cold) also is dehumidifying the air that goes through it. That water collects in the box and drains out the drain hole. This is why you see a small puddle under cars sitting there with the AC on and draining. Both the front and rear air boxes have drains.

If you don't see any collection of water under your car when idling for a while, your drain line could be plugged. When it plugs, it backs up into the box and you may have some mold forming (that you now smell).

 

[Fastcar]

Change the cabin filter if it has one. Run the heater on high 20 minutes to dry things out.

 

[rslynes]

Change the cabin filter if it has one. Run the heater on high 20 minutes to dry things out.

2017 doesn't have a cabin filter.

 

[Fastcar]

2017 doesn't have a cabin filter.

Does it have a heaqter? lol If so run it on high for 20 minutes. Wouldn't hurt to spray some sort of mold killer into the air intake.

 

[Charles M]

Thanks for all the suggestions, will try it this weekend.