Windows foggin bad

My windows fog up it starts with the front windows near the mirrors and the passenger side of the windshield. When the defrost is on it gets about 3/4 of the driver side clear and roughly under half of the driver side defogged. My defrost does nothing for the driver and passenger windows....it seems like it only gets extremely bad when its raining...yet it does nothing until someone is in the car cuz ive let my car warm up a few times b4 driving...ive had that one filter by the passenger windshield done last spring. Since then no wet passenger floor. Whats the deal any one with any ideas>?? My fix so far is crackin each window about an inch its getting old because today was 25degress with snow lol HELPP!

99gtp 143k miles

Check the drain for the heater. It sounds like it may be blocked. It is located on the firewall on the passenger side. Run a coat hanger in the hole and if it is blocked it should dislodge the blockage. Also make sure that the heater core isn't leaking as this can cause excessive fogging as well.

how do i check the heater core?

thanks

You can check it by starting the car and bring it up to temperature. If you have the fan out you should see water leaking from the core. I really doubt that the core is leaking since you didn't say that you smelled antifreeze when the car was running and the heater is on. Also if you aren't losing coolant then I wouldn't worry about it.

Thanks a lot ill check it out

Can you show a pic of where the drain is or possibly describe it a lil more...sorry

thanks

Another site is telling me try a coolant flush...i had one done roughly 6months ago...after my coolant light came on 3weeks after so i put some in it and it went off. I never had a problem with the coolant light coming on b4.

do you smell anti freeze in the car are is it wet in the floorboard on passenger side if so replace heater core

i'd do the coat hanger like he said and if that don't help do the flush and fill..you don't smell ant freeze do you??

You also want to make sure that the air Recycle isnt on and that you're heating the car using fresh air; probably before doing a coolant flush.