Service Bulletin refering to water leaks in Trailblazers


Original poster
Jan 31, 2012
Recently I was having problems with water soaking the drivers side floor mat during heavy rain or a run threw the car wash. There is another post on this site with a TB owner having the same problem and there is some useful info in there also. I started a new thread because I was able to find a service bulletin referring to this type of problem with different causes and remedies.

This was a extremely frustrating process for me. About four months ago I had a new windshield installed and because of this everyone (including myself) kept pointing toward the windshield and if not that the sunroof. I thought for sure the bone head who installed the window screwed something up or there was a problem with the drain hoses running from the sunroof... It was neither of these things.

So after going back and fourth with the glass company, trying everything under the sun to fix it, failing about five times, and taking most everything apart and inspecting it. I finally found it! Here is bulletin that helped me.








The problem in my case was cause 3 and 2. I corrected cause 2 with a little bit of sealer in the top right corner of the windshield. After I did that I did a water test and got the leak to slow down drastically but not completely. I was devistated, I thought I finally had it licked but I was wrong. I didn't know what to do at that point and it wasn't until I was putting the reveal molding back on that I noticed a tiny bit of scuz around the top hole for the screw on the A pillar indicating mouisture. I sealed all the nuts with silicone, let set over night. and once again tried the water test only difference was it worked this time!!!! No water!!!... at all!!!

Just got back from the car wash and it is definetly leak free. Thank God!

I didn't really use the right products to seal but whatever at this point. It worked for sure the way I did but you could also try using the part numbers in the bulletin and getting the right stuff like the screws with the washers that seal when seated.

Now I can go back to enjoying my ride. :thumbsup:

On another note when I had the windsheild wiper cowl off I replaced the windsheild wiper control arms and the screen that was under the slotted vents on the cowl. The screen was pretty rusted and worn, plus filled with all kinds of crap. I think it made a huge difference and looks great now. The arms I got on ebay for about 40$ for both and the screen from home depot for about 7$ and 4$ for the plastic epoxy to mount the screen. Here are some after shots, no before sorry.



I hope this saves someone the aggravation that I endured.

Take it sleezy
Willygood :biggrin:


Oct 26, 2012
Great post. I had water on my left passenger side. I knew it was not the heater core, because it only occured after rain. I did not dissamble anything to track the leak. I tried the same things you did. I siliconed the top of the A pillar (under the rubber cap at top corner of windshield), and siliconed around all 4 screws holding the weatherstripping. Now, I have no more leaks. I am so thankful for this post. I am not sure, but I think my leak started after going thru an automatic car wash. Maybe it loosened up the weatherstripping or the rubber cap.

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