in my 2008 ford Ranger Sport with a V6. The smell reminds me of one winter when I had stepped in dog **** and didn't know it until I was four miles down the road and the heater was on full blast. The smell floods the cabin when the heater is first turned on and warms up, but dissipates after a while. (And I don't have dog **** on the floor boards or on my boots.)

The smell does not come out the AC vents or when the AC was operated this past summer.

Any ideas.

 

Even though you are not using the A/C, the air for the heater still goes through the A/C coil and the A/C box. A lot of water flows through the A/C box in the summer when it's running, and the drain can get clogged, and whatever is in the bottom of the box can rot and smell stale if the drain gets clogged.

I think I would pull the blower fan out and see if that gives you access to some of the ductwork and A/C box, and see if you can figure something out.

 

Dead rodent in the duct work?
Seen it happen........

 

Is removing the fan blower the easiest way to inspect the ductwork?

How difficult is it to remove?

Thanks for weighing in, guys!