If water is getting into the passenger footwell one or more of the weatherstripping has failed. Check the doors as the weatherstripping makes a funned to drain a lot of the water. If there is a leak that can be leading into the cabin of the car.
the heater core is leaking or ac drain is stopped up
if your car has got air con and you had the pollen filter changed, check to make sure the cover was put back on properly
Typically that leak is caused by a leak in the heating system. The heater core is under the dashboard, just above the passenger side.
Have the coolant system pressure tested, the pressure test will increase the coolant leak.
water pump
If it tastes and smells sweet, you have a leaking heater core. If it is just water, you have a leak at the windshield or the A/C condenser drain line is clogged.
Does it leak on the passenger front flooor?
On your Ford Explorer , 4x4 , you have a leak at the PASSENGER side front axle seal ( I have had my passenger side front axle seal changed 3 times now on my 1995 Ford Explorer ) The seal doesn't cost very much , the cost is the labor and I would say it takes about 1 and 1/4 hours to do the job
Dry up the water. Take the car to a car wash and spray it good around doors and windows. If a leak is not visible then check the floor during rain storms while driving to see if water is coming in through a leak in the floor.
In most cases an air conditioner leak on the passenger side where coolant leaks is due to either a broken hose near the back of the footwell, or from the blower motor dying out and causing a backup that breaks a seal. Simply remove the glove compartment by unbolting or unhooking it and take a look around to see if you find any damage in the area behind it, or use a light and look near the back of the footwell for an leak signs of any hoses that may be visible. If you can't find any problems, you may be better off seeking a qualified mechanic.
Hi there in most cars not just in meganes if the leak is inside the car in either the drivers side or passenger footwell its normally the heater matrix which is located behind the dash board. But check under your carpets first as you may have a hole in the floor which would let in in rain water wen driving. Try to remove the covers that are just below the front window (those with holes in them). They are easy to just snap off. Chance is big that you will find this area filled with water. This is due to a drainage hole that tends to get clogged on meganes.