When cool to cold weather, for the 1st few minutes, when car is cold, we sometimes get what some describe as an electric burning smell coming from the heater vents. It seems to go away after a few minutes. Do not notice smell until car cold again. Has not happened in the summer time (warm weather).
Just a guess, but likely dust or other foreign substance on your heater core. I had one vehicle that always had an odd smell when heat was used. You might change your cabin air filter, if equipped.
Have you checked the cabin air filter?
If anything gets past the filter and comes in contact with the blower motor resistor which gets pretty hot,
it can cause a burning smell in the vents.
Good ideas above. I bet it is one of those. Besides those, leaves & twigs getting sucked into the air vents can obstruct the blower’s fan cage too. That might increase the current needed for the motor to start, and could cause this symptom.
Removed filter for testing, nothing on filter except a little “dirt”, noticed that the charcoal on filter was on the internal side of the filter (label says air flow that way). Maybe labeled wrong from manufacture and charcoal causing smell?
Thanks all, replaced cabin filter and smell went away After a few days, looks like it was the cabin filter with charcoal that caused the smell.
it is a good chance that old filter was restricting the airflow to the point where it was not sufficient to cool down the speed control resistor, thus overheating
There was no restriction, you could see light through it, was less than 5000 miles since installed. The smell was only after the weather turned cold, and then only on cold startup.