2000 Bonneville SSEi has wet floor

My 2000 Bonneville SSEi has been randomly stalling. Based on some of the posts on the forum, I checked the wiring harness on both sides. I was surprised to find out the sponge material under the carpeting on the passenger side was soaking wet. I have to believe the wiring harness in that areas was wet also based on the amount of water. I did not find the sides of the carpeting to be wet, only the flat area where you place your feet. Not sure where it is coming from. I have a hunch that the sunroof might have something to do with it although the drains work great. I did notice the sunroof was not sealing tight at the back side. I could not get it to seal. Pressed the switch and it would go to the vent position but not the final seal position. If the drains are working, (poured water into the drain trough), is there any other way water could come through the roof and get to the floor. The top side of the carpet was not wet. Only the under side. Soaking wet. Musty smell in the car also. Anyone have problems with the sun roof not closing tight. What was done to fix it? Any help would be appreciated.
Thanks.
Bob

Have you been using the A/C? Is it humid where you live? If so- does your car leave a nice puddle on the pavement after it idles for awhile with a/c on? If not- check your condensate drain plug on lower passenger side firewall- is it plugged? is there a rubber elbow on it? there should be. Water may be backing up into the drain pan and running out through the vent seals down into your carpet....worth a look I think....

My 2000 Bonneville SSEi has been randomly stalling. Based on some of the posts on the forum, I checked the wiring harness on both sides. I was surprised to find out the sponge material under the carpeting on the passenger side was soaking wet. I have to believe the wiring harness in that areas was wet also based on the amount of water. I did not find the sides of the carpeting to be wet, only the flat area where you place your feet. Not sure where it is coming from. I have a hunch that the sunroof might have something to do with it although the drains work great. I did notice the sunroof was not sealing tight at the back side. I could not get it to seal. Pressed the switch and it would go to the vent position but not the final seal position. If the drains are working, (poured water into the drain trough), is there any other way water could come through the roof and get to the floor. The top side of the carpet was not wet. Only the under side. Soaking wet. Musty smell in the car also. Anyone have problems with the sun roof not closing tight. What was done to fix it? Any help would be appreciated.
Thanks.
Bob

Bob,

There are a number of reasons that you could be getting a wet floor. I have a 2002 Bonneville and I am quickly becoming an unwilling expert on interior leaks of the Bonne. At the moment, my seats are out, console out, carpets out, door trims removed, etc. Previously I dropped the headliner and have reinstalled it. Here is what I found.

1) Sunroof leaks: Sunroof has four drain hoses leading water away from a catch tray under the sunroof. The rubber seal on the glass is not intended to be a water seal. The engineering intent is to catch water in the drip tray and then route it through the tubes to the exterior of the car. Here is the catch. The tubes have several connections. First, a rubber boot secures the tube to the catch tray. It can come off. The tube itself is just a pressure fit into the boot, and can separate (mine did). And finally each tube has a connector just before passing through the body to the outside. These can separate (mine did, when I used an airhose to unclog them) The front tube connectors are on the side kickplates up under the dash. A heavy rubber mat is pinned to the floor and has to be sliced to get access. On the driver's side, the emergency brake has to also be removed. The rear tubes are connected in the trunk, immediately behind the wheel wells. You can more easily access them by removing the trim held in place with a couple of large black plastic push pins. You would be surprised where the water drains to from these leaks. One of mine was running out of the weatherstrip below the front door. I followed it up the weatherstrip until it reached the headliner. This was the separated sunroof drain tube.

2) Door Leaks: Another source of leaks is the doors themselves. Water flows into the door through the window channel and is suppossed to flow out through weep holes in the bottom of the door. The door inner has several large openings for access to the various machinery in the door. To prevent water from coming out, GM engineered a large formed polyethlyene sheet, that is adhered to the door inner with a strip of mastic from a caulk gun. There are actually hills and valleys in the caulk design on the lower edge, and each valley has a small drain hole to let water flow back into the door. After years of hot sun, the polyethlyene buckles and the mastic releases, and water just flows straight down past the door trim and into the car. I tried just reseating the mastic and found that it again released after just a short time. I am trying silicone caulk this time, to see if I can get the polyethylene sheet to seal once and for all.

3) Other Leaky Areas: Others have found leaks coming from their firewall area, and of course the AC condensate drain as suggested earlier. If you see a puddle under the car when it idles with the AC on, it's not plugged. The AC drain hose is designed to be closed until a water column builds up to cause it to open.

There are lots of comments on this issue in various forums so it must not be so uncommon. I found information in the Pontiac Bonneville Owners Forum wwwpontiacbonnevilleowners.com and in the Edmunds Pontiac Bonneville forum. You might try these as well.

Best of luck.