I have a burning smell, like a circuit board or motor overheating, coming from the vents when I turn the heat on. There is no smell outside the car or in the engine compartment.

The fan and heating system seems to be working properly. Someone said that there are two fans so perhaps one is sticking? I had heard a screeching sound on and off from the fan the week before this smell arrived.

Can someone suggest a way to find out what is wrong? What might happen if I do nothing?

Thanks,
Jerry

 

There is only one blower fan. Don't worry, if it is the smell of burnt electrical components you should find out very soon what it is.

 

I did buy a fire extinguisher that now rides on my front seat. My concern is that I do damage by not fixing this. Is the blower easy to find or does the entire dash need to be dismantled, in which case should I buy a new motor ahead of time?

 

You won't see flames. A fuse will blow long before that happens. The blower motor is somewhat of a pain to get to, but here is the procedure. http://www.mercedesshop.com/Wikka/W124BlowerMotor