Interior passenger floor pans, front and rear wet after rain. Will pursue clogged drains but not sure how to get to them right now. Resealed rain diverter plastic on RH door to no avail. Now to attack clogged drain tube in cowl area. Had similar problem in my '64 1/2 Mustang caused by air intake in front of windshield due to corrosion in the intake plenum. I don't think the 05 and the 64 are made the same but good grief, here we go again?

Update from Oct 7, 2019: After watching three YouTube videos, I learned there are 3 possible causes. One COULD be a loose rain diverter plastic shield on the inner door structure but the most likely two causes are clogged drain grommet valves in the lower part of the air intake plenum which are visible on the firewall in the rear of the engine compartment, if you use a good flashlight you can see both of them (PAX and Drvr sides). One is on the passenger side and one on the driver side. You can stick your finger up and into these two rubber drains (actually almost two small fingers will fit into them) and dislodge the rotted leaf and seed debris and once again allow the water that comes down your windshield to drain from the plenum bottoms. You will have to remove the wiper arms which requires the use of a tie rod end puller in order to remove the drivers side leaf screen (cowl) shield. The passengers side, plenum drain, will also clog up with rotted leaf decay and water will rise to the level of the cabin air filter and bingo, it enters the cars interior - you will have flooded passenger floor area. You can't see it dripping in anywhere (unless you are extremely lucky) as it just runs down behind the carpet liner where your feet contact the interior of the engine compartment firewall when you're sitting in the seat as you would ride normally.

The replacing of 10 retainers and their malleable (when heated during installation with heat gun) seals just below the bottom edge of the windshield exterior is also very strongly advised as they deteriorate after a few years.These 10 oblong holes hold the retainers that receive the ten feet that snap into them on the two upper cowl covers. Also see the YouTube video "2007 Ford mustang water leak fixed". It is the same as my 2005 Mustang. He calls them "grommets" . Ford calls them "retainers" p/n 9R3Z-63517C58-A ($8 to $10 each). To pull the wiper arms I used a "Performance Tool p/n W83025 Tie Rod End Puller available at Advance Auto Parts or elsewhere. Doesn't line up precisely, but pulls the wiper arms for sure, with hood up.

Update from Oct 7, 2019: See pictures showing wiper arm before and after pulling with tie rod end puller, one pic showing drain on firewall, one looking straight down into the plenum showing the rubber drain at the bottom of the plenum and another showing the location of the rubber drain on the firewall behind and above the silver colored line (drain is black rubber)

Update from Oct 8, 2019: Installing the 10 "retainers" with a heat gun is tricky. You have to heat the rectangular sealing material (with "retainer" in the hole, naturally) until it begins to soften. It becomes soft and you can see when it is hot enough to become adhered to the paint with pressure. Maybe 20 seconds or less (don't burn your paint). Press it down with something or with protected fingers so it doesn't burn your finger tips. When it cools, in about a minute or so, you can tell it's in place good. When you're ready to reinstall the two cowl covers take a good look at the feet that snap into the "retainers" to be able to judge if they have snapped in good, looking at them from the outside, through the top slots in the cowl covers, with a GOOD BRIGHT flashlight. The two extreme end inserts can be knocked out of their holes if you are not really careful maneuvering the cover feet into place. When you think you've installed them correctly carefully raise up the end of the rubber seal that contacts the windshield and look at each of the two end inserts, one at a time. You'll be able to see it with a GOOD flashlight. You may have to put your thumb down behind the rear end of the hood a PUSH it in completely. GRUNT a little.

If the long rubber seals that contact the windshield look wavy, looking across the two cowl covers, then one of the feet probably isn't snapped into one of the retainers. I had to remove the passengers side, cowl cover to reinstall the end retainer because I knocked it out during installation. Had to re melt the sealant material with the heat gun, again. Be real careful with the heat gun. Watch where you point that thing.

Update from Oct 14, 2019: 3 days to dry out using fans after halfway pulling up front carpet. Panel covering fuse box comes out by pulling panel held by 5 or 6 retaining clips of two kinds (with moderate effort). Allows front carpet to be halfway pulled up and foam liner to be partly pulled up. Used several empty poweraide bottles to hold up carpet. Used powerful electric leaf blower with snout in rear carpet (not pulled up or removed). Ran leaf blower about an hour to dry. Treated moldy smell with spray bottle of Mold control front and back as blower forcing air under rear carpet created a bubble under the rear carpet. Mold control sprayed under carpet (into the bubble) killed the mold odor. Then used odor neutralizer to be extra diligent. Worked good.

Not sure whats causing the problem yet but as soon as I get the floorboard dried up it's wet again.

Update from May 28, 2016: The water was getting in through the vents below the windshield.Under the vent plate(Under hood)there is what is called Grommets there is 1 on each side and they get stopped up with dirt etc...and causing the water to run over onto floorboards.Taken the Grommets out and problem solved,there not needed so not sure why they were even put on the car.

Take the splash shield off that is in front of the windshield and under the windshield wipers. There is an open cavity under there that collects the water when it rains and drains it to the ground. There is a rubber grommet around the drainage hole that is a poor design and gets clogged easily, I tried cleaning it and changing it but it still kept clogging and dumping water inside my car, finally I removed the rubber grommet and have been water free for two years. After you fix this replace your cabin air filter because it will be all moldy from the water. Good luck

Bought this car used, not an issue with it, except for the notorious cluster problem. Car started leaking water at 48k miles, just a little bit of water under the glove box on the passenger seat side. The problem persisted and started leaking ALOT. Everytime it rained it would pour water into the car. The floorboards were always soaked. It finally got so bad that the right front headlight and the rear right taillight would stay on and not go off. Brought this to a Ford Dealership, the problem was very insignificant but something to keep your eye on. The tech told me that the air conditioning duct was clogged, (there were 2 ducts) He showed me just a big clump of mud dirt leaves and what have you. Hence, the water was not draining properly and slipping into the car. Unfortunately, If i brought this in earlier i wouldnt have had to drop $700 on a new composite box for the headlights, because once water makes contact, its fried. Otherwise it would have been a $5 job. Lesson learned. Go get those ducts checked! Easy fix! Tech also told me its a bad design from Ford, and it should be cleaned out at least twice a year. Bon voyage.

My son got married on Sept. 30, 2011. Since he is a med student in Georgia, he spent the night at a hotel, came to a family breakfast and his Mustang would not start. On the way home his new wife said her foot was wet and couldn't figure out why. It was towed to our local garage in Willard, Oh and they told us that the wiring and the computer parts were fried, actually corroded due to a leak, and we were quoted up to $5000 to fix it. It needed special order parts and they did not come assembled. The dash has to be pulled to fix it. Not a simple problem. Evidently although my son has treated this car like his child and always kept up with the servicing, this leak was not detected and caused untold problems. The mechanics informed us there was a Technical Service Bulletin out for this problem. It states"Summary: Ford vehicle may exhibit a difficult to diagnose water leak in the front floor area.May be caused by loose grommets and/or sealer strips around the cowl area, loose a-pillar window weatherstrip retainer.*pe " This report was dated May 4th, 2009 and the component was considered "structure." For anyone wishing to look this up it is called "2002 Ford Mustang Structure Service Bulletin 235322" The problem is that this can occur on any Mustang from 2005-2009, so it is not just his year that is involved.

We tried turning in to our insurance, but they turned us down as it was not in a flood and not in an accident. Ford Motor Co. refused to help as it is out of warranty. This is a factory defect and they won't cover it. It isn't a recall yet. What infuriates me is that they tell the Ford Dealerships but do not warn the consumer. My son was lucky his car quit in a parking lot in his home town close to our local dealership. What if it had happened on the road, caused an accident, injured my son and his new wife or worse. What if it had happened on his way back to college in Marietta, GA. This the day after his wedding on top of it and him having to drive back to GA the next day. Obviously he couldn't drive it back to school and obviously he had to have a car. We just purchased a new Ford F-150 this summer and a new Ford Focus. So much for customer loyalty. We were to turn in our old lease on a Mazda 6 on Oct. 8 but had to renew the lease for a month so he would have something to drive back to school. Medical schools could care less that you are stranded out of state when classes start. We also have to reinsure the Mazda 6. So we are now paying insurance on our 2 new cars, our old lease, a Mustang going nowhere for awhile and our daughter's car. How nice for us in this economy. And Ford refuses to help us. Out of warranty. What a way to cover your company's liability by covering factory defects only if the car is in warranty. Furthermore, thanks for letting my son know about this defect when it was a simple leak, before it turned into a HUGE problem costing thousands. Thanks for caring about your loyal customers and their safety and pocketbooks. This is Ford's fault and they should take responsibility. After all no one told our son about this problem when he had his car serviced at a Ford Dealership in another state. Unless this becomes a recall, or our insurance company or Ford Motor Company decide to grow a conscience, we are out a great deal of money. Funny how manufacturers in this country used to take pride in their work and back their product but anymore, they try to legally get out of taking responsibility in any way possible. Wonder what we will buy the next time we are due to get two new vehicles. To any Mustang owners out there, go online, go to your dealership, don't let this happen to you. And if you have had a problem of this sort, please report it. That is the only way recalls are born. I have complained to many sources, but if anyone knows how we can get Ford to honor their responsibility, please let us know. Thank you for letting me vent.

Ford Mustangs has always been a heart of mine. I have the color, make, model & body style I have always wanted. However, I have a problem with getting into my car & there's water all on the floors messing up my favorite pairs of shoes!!! I would like to know where the water is coming from. It is a good thing that you can't really see the damages it is causing because the rugs are a dark color. The car smells mildewy, which I hate...If any one have a solution, it would be greatly appreciated! It seems like it only gets wet after it rain or we wash the "Stang". Have a bless day and drive safe!