After I spray washer fluid on windshield (the spray/wipers work ok) the inside of the car is filled with a strong odor that seems to come through the heating/ac air vents. The heater/ac does not need to be on to smell the odor. Why?
washer fluid odor inside car on 2007 Ford Expedition
I suspect algea is forming in the washer bottle, drain out the washer bottle try using some of the blue pre-prepared washer fluid in the washer bottle and perhaps add a little bleach to the bottle to kill any remaining algrea. If there is bacteria in the actual heating/air conditioning ducts spray some Lysol aerosol disinfectant in the air ducts let it settler for a few minutes and then tun on the fan. Spray some Lysol or similar product in the air intake near the wiper panel as well with the fan on.