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.
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.
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.
Where is the drain on the driver side firewall