Leaky Sunroof


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A few months ago I fixed an issue where the sunroof on my H3 Hummer wouldn’t properly drain the water. This makes for a spectacular surprise after every single heavy rainfall. The problem was from going off-road with the Hummer and flinging mud and debris everywhere with the sunroof wide open. By design, all sunroofs leak which is why they have tubes to drain the water. If the mud and debris are forgotten about and never cleaned out, it tends to get jammed in the tubes. Once the H3 Hummer sunroof tubes are clogged, the water has no way drain out except out of the sunroof and sadly into my lap.

Fixing the clogged sunroof drains is a simple process. On the passenger side, you need to remove the plastic panel on the side of the dash to gain access to the lower portion of the drain tube that has this bent shape. This lower piece is white and has a black grommet on the firewall to drain the water outside of the vehicle. The upper portion is just a flexible black hose. I decided to disconnect the two hoses and use 125 PSI air pressure from an air compressor to blow the dirt and grime back out the way it came in. Be sure to point the other end outside the vehicle, because I didn’t the first time.

The plastic cover for the pillars on both the driver and passenger sides I found to be extremely easy to remove. Be careful with the plastic pillars because of the tiny speakers called tweeters are attached to the backside. I put a rag on top of the sunroof and end up blowing out the upper portion of the tubes using the air compressor opposite of how it drains. A bunch of debris came out again, remember to hold the rag down when clean out the drain tubes again using the compressed air.
H3 Hummer Dash Panel Removal Fxing Leaking Sunroof Clogg
If you look at the featured image at the top of the page you see the black rubber grommet on the white hose that makes up the lower portion of the drain hose for the sunroof. The outside of that grommet is inaccessible under the hood of the vehicle, which is why I pulled it off the firewall for cleaning. To reinstall the grommet back into the firewall, feel around with your fingertips to find a flat metal hole on the wall. Installing it will take a bit of effort on the passenger side. However the driver side is easily reachable, but taking pictures of it didn’t work out for me on either side of the vehicle.
H3 Hummer Side Panel Removed Leaky Sunroof
There is rearward sunroof drains on the H3 Hummer too. Fortunately for myself, I never had to gain access to those tubes because they were never clogged for me. The process was a bit of learning experience for me because I made a few mistakes, but overall it took just a couple of hours. Looking back, if I had the chance do it again, and knew what I know now, cleaning out the drain tubes on the sunroof would only take myself 25 minutes.

If you have any questions, please don’t hesitate to ask me below in the comment section.

  1. Bryan Avatar

    Where is the drain on the driver side firewall

    1. Schwarttzy Avatar

      Basically the same place that the passenger side firewall drain is.

    2. Alexis Melendez Avatar

      I’m not mechanically inclined and I usually break stuff when I try what is yhe best way to resolve the problem. I JUST GOT MY H3 and the carpet is soaked

      1. Schwarttzy Avatar

        You should to take it to a mechanic if you’re not inclined. Tell the mechanic that sunroof drains are clogged and need to be cleaned out. I recommend completely dropping the sunroof and cleaning all the mud and debris out because it will just clog those tubes up again.

  2. I need some help, I have an 2008 H3. I had the dealership clean the drain tube, check connections behind pillar and check rubber grommet on firewall. They tore the whole dash apart in the process to find the leak. I sill have a water leak coming down from behind the glove box after they checked everything. Thoughts on what else might be causing this?

    1. Schwarttzy Avatar

      There’s no way for me to be certain, but the issue continued for me until I clean the drains in the rear too. In your case, it seems like they didn’t connect the drain behind the glove box properly.

    2. Hello, I just fixed my sunroof drain leak behind the glove box. You should check that the tube on that side is still connected properly at the sunroof itself. By this I mean where the drain starts at the sunroof. It’s really easy to just unhook your passenger side visor and gently pull the headliner down and you can see where the tubes connect to the sunroof. If the dealership didn’t do this I bet that’s the problem. If you have any questions let me know.

  3. I had the driver side grommet out, I blew both sides out with compressed air, but it still has a slight leak, is there an area where the hose separates and could just be loose?

    1. Schwarttzy Avatar

      The sunroof drain tubes only have two connections so I don’t think there is an area where the hose separates. Keep in mind though that there are four connections that I’m aware of.

  4. I only notice the two drain holes in the front, my h3 sits on a slight hill in my drive way so the water leaks in my sunroof and goes to the back. Are there drain holes back there that I’m missing or does it just fill to that point and then drain, because when it pours it even starts to come through the Mic hole in the headliner

    1. Schwarttzy Avatar

      There are drain holes on both sides right behind the rear passenger’s seats just below where the seat belts are attached.

  5. Goober Schnot Avatar

    I just cleared my driver’s side with pipe cleaner attached to a metal wire string (the type for hanging picture frames). I drilled out the poorly designed rubber grommet and put it back in. However, we had a big rain last night and my floor mat was all wet! Luckily I had weathertech mats that kept a quart of water from flowing into my carpets. This was because I inadvertently yanked the hose out from where the tube meets the roof. I had to remove the A-pillar cover (one screw), the three screws on the visor, and slightly pull back the rubber seals around the door to access the tube from inside the headliner (driver side). Pushed the tube back in and tested with a cup of water. NO leaks inside! Water properly drained outside. Not a hard job to do, very easy.

    1. Thanks for the roof pipe leak tip, i tested everything besides the pipe connecting to the roof drain itself, i dont know how it got loose, but it was the problem

  6. Something to watch for in the rear sunroof drains are kinks in the rubber pipe as it bends 90 degrees down the rear door seat belt pillar to the rubber nipple outlets. On my right hand drive 2008 H3 this was particularly bad on the passenger side as it passes over the side airbag and down the pillar. Also the 90 degree bend was higher than the outlet at the sunroof itself which compounded the problem. I modified this by cutting the 90 degree bend out and replacing it with a hard plastic bend which is inserted into the rubber pipe. It takes several hours to do and the headliner requires lowering at the rear but it works perfectly now.

    1. Tonneau Cover Avatar

      Good tips. My buddy’s H3 having some slight leak and we suspect the rubber pipe angles might be causing the issue. We will take a look.

  7. 06 h3 hummer sunroof leak drivers side. The piller you said that was easily removed is that the one that has th small speaker and the round airbag tag. Do you just pry that off or is there something else?

    1. Schwarttzy Avatar

      There is a little tab that needs to be popped off, to reveal a Philips screw that needs to be removed, then carefully pop the plastic off.

  8. Stanley Avatar

    I can’t find anything online describing or showing where the rear drain tubes exit on an H3T. The bed is separate, so it’s not going to be inside thecrear fender like on the H3. Do you know?

    1. Schwarttzy Avatar

      The drain tube for the sunroof should be behind the plastic where the seat belt attach. I would guess at 2 feet lower inside the frame.

  9. David Banks Avatar

    Did anyone have a problem with auto door locks not working and backup lights going out after water leak from sunroof? Hummer H3 2009. Can’t find the wiring or antenna in passenger side dash.

    1. Schwarttzy Avatar

      Hey David!

      I haven’t experienced that issue myself and don’t know of anyone that has personally. I think messaging on one of the forums or Facebook groups would be your best bet.

    2. I have the same problem with my H3, remote control to lock and unlock don’t work no more also end total I had a problem that the ABS and hand brake lights up on the dash.
      Ik think that de body control module is broken

      1. Schwarttzy Avatar

        I recently put some dielectric grease on my antenna attached to the BCM, Body Control Module. Also, worked on making sure the connection was tight and that fixed my issue with the remotes not working.

        ABS is possibly a torn or damaged sensor.

        I would check the connection on the E-brack to see if it has been tampered with.

  10. Justin Mercuri Avatar

    Just curious, I’ve done the front drain tubes, worked like a charm, now its leaking again though its getting the A-pillar wet. I’ve also heard that it could be the ‘onstar/gps’ antenna that is up there. Ever have to seal that too, by chance? Gotta wait for a non-raining day to get the headliner down and the forward passenger side upper attachment point checked, but figured if I’m in there, might as well seal that too, eh?

    1. Schwarttzy Avatar

      I would check if the tube hasn’t become disconnected in the ceiling. Also, don’t forget the rear tubes too.

  11. Jeb Johenning Avatar

    I too have been working on the best way to clear the Hummer H3’s clogged sunroof drains.

    I think I have the best solution for cleaning the Front drains ( & maybe the Rears).

    Purchase a large medical syringe (at least 2-4 ounce capacity) from the drugstore and some 90% rubbing alcohol. (Water will also work but rubbing alcohol works great for dissolving the grease, grime, dirt, and mold that accumulates in the drains.)

    1. Remove the lower end of the drain hose from the firewall grommet.
    2. Fill the syringe with Rubbing Alchohol
    3. Connect the syringe’s tapered tip to the bottom end of the drain tube.
    4. Gently inject about 20% of the alcohol into the drain tube and then withdraw the alcohol back into the syringe. Repeat several times, each time adding a bit more alcohol into the drain tube. By Agitating the alcohol in the tube several times, the tubes will be cleaned of MOLD, DIRT, and DEBRIS. (If the syringe becomes filled with debris, flush the syringe and refill it with clean alcohol.)
    5. Once the fluid runs clear after repeated cleaning, ReConnnect the drain tube to the firewall grommet.
    6. Squirt a few ounces of alcohol into the upper end of the drain tube inside the sunroof and verify that fluid flows freely into the fender well and onto the ground.

    Finally, I highly recommend modifying the drain grommet by clearing the center “butterfly flaps”. This process is well documented by others in other DIY fixit threads

    BTW, I can’t seem to locate any who sells new firewall drain tube grommets. Does anyone have a web link and a part number for the front drain grommet? Thanks!

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