Honda Repair: odor from heater, honda accord, evaporator

Question
hi,
    my husband owns a 94 honda accord, and lately, every time he turns on the heater, it literally smells like dog s*** (excuse me, but it does smell like that).  it did it for a little while with the ac too, but now i think it stopped when we use the ac, but it's still terrible when the heater's on.  do you know what can be causing this?  thanks!

Answer
Mary,
Sounds like you have mold build up in the a/c evaporator. That is the part of the a/c where water will sit. It never gets sunlight and is usually a cool place. That is what mold thrives on.
What you need to do is keep the vents on fresh air when you are not using the A/C. This will force air into the evaporator and kill the mold. There is also a product out there that you can buy to spray in the vents to kill the mold. Rep. 70 is the name of one such product. One other thing that will keep the mold down is to shut the A/C off a few miles before you get home but keep the fan blowing in the meantime. This will help eliminate the mold from growing.
Thanks for your question,
Gene