2012 Heater odor

Picked up my truck about a week ago and noticed the odor on the test drive. At first it was there with the AC AND Heat. Have done AC system treatments, sprayed solvents into the fresh air intake and cleaned it out that way.

Now when the AC/cold air is blowing, I have no odor. But when I turn the heat on it smells like black and milds are being smoked in my truck. That's the only way I can describe the odor. It has a hint of sweetness but not the sweetness of Maple Syrup, which would indicate a coolant leak in my heater core.

Any suggestions on the issue or maybe someone has experienced the same issue. Also, I have replaced the cabin air filter and it contained the same smell. Pic below of the old air filter.

 

um sounds like your truck was a smokers truck. clean everything, headliner, seats, carpets. even behind the dash head unit and air ducts.or just put in some charcoal under the seats and behind the center consol under the dash

 

We've began that process. Haven't gone as far as cleaning behind the head unit.

What's the best way to clean the ducts?

 

use Carbon cabin air filter. helps remove odors

 

remove the radio surround and dash speedo bezel the ducting is behind it. as far as the passenger side I'm not sure I have never gone that far into it. I used a rag taped to a flexible wire like a flex magnet or a coat hanger. Ball rag up then tape another one around it and wiped it down with some turtle wax dash n glass. worked for me just be careful not to brake anything and don't force it

 

Ive had luck spraying Lysol in the HVAC ducts to kill odors