As the air conditioning system provides cool air by letting air which passes through the evaporator and recirculates within the cabin ( inside of the car). however the air conditioning system can also allow outside air to be drawn into the cabin via the recirculating air duct which is connected to the outside air duct. Through the outside air duct, when the car gets old, the seal is no longer able to hold into position to prevent dust, stones or water from entering the cabin. as a result, the blower motor for the air conditioning will wear out faster and also the evaporator will spoil easily. this also results in water entry into the cabin via the outside air duct.
Here are the steps and guides to prevent it......
First you will need a plastic water bottle (1.5L) and cut the top and bottom part off. (see above fig. 1) after that, take the middle part and cut on one side (follow the read line fig. 2)
Next open and remove the front cowl top grille (located at the front of the car windscreen wiper arm area) and remove the small box cover ( depending on the type of vehicle and placing of your air duct location )
Locate the outside air duct which is located at the side of the hole and place the cut bottle on top of it like so (see fig. 2 above)
After all that is placed and done, fit back the small cover box and the cowl top grille. Hopes this tip will help to prevent future water leaks, dust or debris from entering your ride. :)
Any question or suggestions feel free to comment about it :)