Steam comes off my car hood when it rains/snows while I am driving? How come? Windshield also fogs up badly.?

If water is coming in through the tail lights, you'll need to track that leak down and fix it so water can't get in. Usually, when the interior windows fog up excessively, it indicates that water or possibly coolant is pooling somewhere and adding humidity to the interior of the car. This also happens when the heater core is leaking and coolant pools in the bottom of the heater core box where the air circulates and is heated and then blown into the vents by the blower motor. The fresh air intake may also be plugged up with debris (leaves, dirt, etc. and is not draining properly) or it might be a leak around the windshield or weatherstripping around the doors allowing water to come in when it rains. This is going to be a process of elimination.......Check the carpets to see if they are damp or wet anywhere and then look for leaks above that point (since water runs downhill). With your car being 20 yrs old, I would also check to see if the floor boards are solid and don't have any small holes that have rusted through, allowing water to spray up through them and wet the carpet from underneath. You may have to pull up the carpet to check them. Good Luck